From 52f9ecfc4dac65d305fd920e8c7f748889a0804f Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 12 Aug 2019 23:24:48 +0200
Subject: Move api into its own crate

---
 dhall/src/core/mod.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/mod.rs b/dhall/src/core/mod.rs
index a202e72..0667df8 100644
--- a/dhall/src/core/mod.rs
+++ b/dhall/src/core/mod.rs
@@ -1,4 +1,4 @@
-pub(crate) mod context;
-pub(crate) mod thunk;
-pub(crate) mod value;
-pub(crate) mod var;
+pub mod context;
+pub mod thunk;
+pub mod value;
+pub mod var;
-- 
cgit v1.3.1


From 1ed3123aeb3c9272b6810605a7ee781c42095f09 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 13 Aug 2019 17:20:35 +0200
Subject: Swap Typed and TypeThunk

---
 dhall/src/core/thunk.rs | 125 ++++++++++++++++++++++++++++++++++++++++--------
 dhall/src/phase/mod.rs  |  95 ++++++++++--------------------------
 2 files changed, 129 insertions(+), 91 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index f41579c..740ecbc 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -1,15 +1,18 @@
+use std::borrow::Cow;
 use std::cell::{Ref, RefCell};
 use std::rc::Rc;
 
-use dhall_syntax::{ExprF, X};
+use dhall_syntax::{Const, ExprF, X};
 
-use crate::core::context::NormalizationContext;
+use crate::core::context::{NormalizationContext, TypecheckContext};
 use crate::core::value::Value;
 use crate::core::var::{AlphaVar, Shift, Subst};
+use crate::error::{TypeError, TypeMessage};
 use crate::phase::normalize::{
     apply_any, normalize_one_layer, normalize_whnf, InputSubExpr, OutputSubExpr,
 };
-use crate::phase::{Type, Typed};
+use crate::phase::typecheck::type_of_const;
+use crate::phase::{NormalizedSubExpr, Type, Typed};
 
 #[derive(Debug, Clone, Copy)]
 enum Marker {
@@ -42,7 +45,16 @@ pub struct Thunk(Rc<RefCell<ThunkInternal>>);
 /// A thunk in type position. Can optionally store a Type from the typechecking phase to preserve
 /// type information through the normalization phase.
 #[derive(Debug, Clone)]
-pub struct TypeThunk(Typed);
+pub enum TypeThunk {
+    // Any value, along with (optionally) its type
+    Untyped(Thunk),
+    Typed(Thunk, Box<Type>),
+    // One of the base higher-kinded typed.
+    // Used to avoid storing the same tower ot Type->Kind->Sort
+    // over and over again. Also enables having Sort as a type
+    // even though it doesn't itself have a type.
+    Const(Const),
+}
 
 impl ThunkInternal {
     fn into_thunk(self) -> Thunk {
@@ -190,39 +202,94 @@ impl TypeThunk {
     }
 
     pub fn from_thunk(th: Thunk) -> TypeThunk {
-        TypeThunk(Typed::from_thunk_untyped(th))
+        TypeThunk::from_thunk_untyped(th)
     }
 
     pub fn from_type(t: Type) -> TypeThunk {
-        TypeThunk(t)
+        t.into_typethunk()
     }
 
-    pub fn normalize_mut(&mut self) {
-        self.0.normalize_mut()
+    pub fn normalize_nf(&self) -> Value {
+        match self {
+            TypeThunk::Const(c) => Value::Const(*c),
+            TypeThunk::Untyped(thunk) | TypeThunk::Typed(thunk, _) => {
+                thunk.normalize_nf().clone()
+            }
+        }
     }
 
-    pub fn normalize_nf(&self) -> Value {
-        self.0.to_value().normalize()
+    pub fn to_typed(&self) -> Typed {
+        self.clone().into_typed()
     }
 
-    pub fn to_value(&self) -> Value {
-        self.0.to_value()
+    pub fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
+        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub fn to_thunk(&self) -> Thunk {
-        self.0.to_thunk()
+    pub fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
+        TypeThunk::Typed(th, Box::new(t))
+    }
+    pub fn from_thunk_untyped(th: Thunk) -> Self {
+        TypeThunk::Untyped(th)
+    }
+    pub fn from_const(c: Const) -> Self {
+        TypeThunk::Const(c)
+    }
+    pub fn from_value_untyped(v: Value) -> Self {
+        TypeThunk::from_thunk_untyped(Thunk::from_value(v))
     }
 
+    // TODO: Avoid cloning if possible
+    pub fn to_value(&self) -> Value {
+        match self {
+            TypeThunk::Untyped(th) | TypeThunk::Typed(th, _) => th.to_value(),
+            TypeThunk::Const(c) => Value::Const(*c),
+        }
+    }
+    pub fn to_expr(&self) -> NormalizedSubExpr {
+        self.to_value().normalize_to_expr()
+    }
+    pub fn to_expr_alpha(&self) -> NormalizedSubExpr {
+        self.to_value().normalize_to_expr_maybe_alpha(true)
+    }
+    pub fn to_thunk(&self) -> Thunk {
+        match self {
+            TypeThunk::Untyped(th) | TypeThunk::Typed(th, _) => th.clone(),
+            TypeThunk::Const(c) => Thunk::from_value(Value::Const(*c)),
+        }
+    }
     pub fn to_type(&self) -> Type {
-        self.0.to_type()
+        self.clone().into_typed().into_type()
+    }
+    pub fn into_typed(self) -> Typed {
+        Typed::from_typethunk(self)
+    }
+    pub fn as_const(&self) -> Option<Const> {
+        // TODO: avoid clone
+        match &self.to_value() {
+            Value::Const(c) => Some(*c),
+            _ => None,
+        }
     }
 
-    pub fn to_typed(&self) -> Typed {
-        self.0.clone()
+    pub fn normalize_mut(&mut self) {
+        match self {
+            TypeThunk::Untyped(th) | TypeThunk::Typed(th, _) => {
+                th.normalize_mut()
+            }
+            TypeThunk::Const(_) => {}
+        }
     }
 
-    pub fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
-        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
+    pub fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+        match self {
+            TypeThunk::Untyped(_) => Err(TypeError::new(
+                &TypecheckContext::new(),
+                TypeMessage::Untyped,
+            )),
+            TypeThunk::Typed(_, t) => Ok(Cow::Borrowed(t)),
+            TypeThunk::Const(c) => Ok(Cow::Owned(type_of_const(*c)?)),
+        }
     }
 }
 
@@ -254,7 +321,14 @@ impl Shift for ThunkInternal {
 
 impl Shift for TypeThunk {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(TypeThunk(self.0.shift(delta, var)?))
+        Some(match self {
+            TypeThunk::Untyped(th) => TypeThunk::Untyped(th.shift(delta, var)?),
+            TypeThunk::Typed(th, t) => TypeThunk::Typed(
+                th.shift(delta, var)?,
+                Box::new(t.shift(delta, var)?),
+            ),
+            TypeThunk::Const(c) => TypeThunk::Const(*c),
+        })
     }
 }
 
@@ -293,7 +367,16 @@ impl Subst<Typed> for ThunkInternal {
 
 impl Subst<Typed> for TypeThunk {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        TypeThunk(self.0.subst_shift(var, val))
+        match self {
+            TypeThunk::Untyped(th) => {
+                TypeThunk::Untyped(th.subst_shift(var, val))
+            }
+            TypeThunk::Typed(th, t) => TypeThunk::Typed(
+                th.subst_shift(var, val),
+                Box::new(t.subst_shift(var, val)),
+            ),
+            TypeThunk::Const(c) => TypeThunk::Const(*c),
+        }
     }
 }
 
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index ccedff2..0b05227 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -4,14 +4,12 @@ use std::path::Path;
 
 use dhall_syntax::{Const, Import, Span, SubExpr, X};
 
-use crate::core::context::TypecheckContext;
-use crate::core::thunk::Thunk;
+use crate::core::thunk::{Thunk, TypeThunk};
 use crate::core::value::Value;
 use crate::core::var::{AlphaVar, Shift, Subst};
-use crate::error::{EncodeError, Error, ImportError, TypeError, TypeMessage};
+use crate::error::{EncodeError, Error, ImportError, TypeError};
 
 use resolve::ImportRoot;
-use typecheck::type_of_const;
 
 pub(crate) mod binary;
 pub(crate) mod normalize;
@@ -33,16 +31,7 @@ pub struct Resolved(ResolvedSubExpr);
 
 /// A typed expression
 #[derive(Debug, Clone)]
-pub enum Typed {
-    // Any value, along with (optionally) its type
-    Untyped(Thunk),
-    Typed(Thunk, Box<Type>),
-    // One of the base higher-kinded typed.
-    // Used to avoid storing the same tower ot Type->Kind->Sort
-    // over and over again. Also enables having Sort as a type
-    // even though it doesn't itself have a type.
-    Const(Const),
-}
+pub struct Typed(TypeThunk);
 
 /// A normalized expression.
 ///
@@ -105,83 +94,63 @@ impl Typed {
     ///
     /// However, `normalize` will not fail if the expression is ill-typed and will
     /// leave ill-typed sub-expressions unevaluated.
-    pub fn normalize(self) -> Normalized {
-        match &self {
-            Typed::Const(_) => {}
-            Typed::Untyped(thunk) | Typed::Typed(thunk, _) => {
-                thunk.normalize_nf();
-            }
-        }
+    pub fn normalize(mut self) -> Normalized {
+        self.normalize_mut();
         Normalized(self)
     }
 
     pub fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
-        Typed::Typed(th, Box::new(t))
+        Typed(TypeThunk::from_thunk_and_type(th, t))
     }
     pub fn from_thunk_untyped(th: Thunk) -> Self {
-        Typed::Untyped(th)
+        Typed(TypeThunk::from_thunk_untyped(th))
     }
     pub fn from_const(c: Const) -> Self {
-        Typed::Const(c)
+        Typed(TypeThunk::from_const(c))
     }
     pub fn from_value_untyped(v: Value) -> Self {
-        Typed::from_thunk_untyped(Thunk::from_value(v))
+        Typed(TypeThunk::from_value_untyped(v))
+    }
+    pub fn from_typethunk(th: TypeThunk) -> Self {
+        Typed(th)
     }
 
-    // TODO: Avoid cloning if possible
     pub fn to_value(&self) -> Value {
-        match self {
-            Typed::Untyped(th) | Typed::Typed(th, _) => th.to_value(),
-            Typed::Const(c) => Value::Const(*c),
-        }
+        self.0.to_value()
     }
     pub fn to_expr(&self) -> NormalizedSubExpr {
-        self.to_value().normalize_to_expr()
+        self.0.to_expr()
     }
     pub fn to_expr_alpha(&self) -> NormalizedSubExpr {
-        self.to_value().normalize_to_expr_maybe_alpha(true)
+        self.0.to_expr_alpha()
     }
     pub fn to_thunk(&self) -> Thunk {
-        match self {
-            Typed::Untyped(th) | Typed::Typed(th, _) => th.clone(),
-            Typed::Const(c) => Thunk::from_value(Value::Const(*c)),
-        }
+        self.0.to_thunk()
     }
     // Deprecated
     pub fn to_type(&self) -> Type {
-        self.clone().into_type()
+        self.clone()
     }
     // Deprecated
     pub fn into_type(self) -> Type {
         self
     }
+    pub fn into_typethunk(self) -> TypeThunk {
+        self.0
+    }
     pub fn to_normalized(&self) -> Normalized {
         self.clone().normalize()
     }
     pub fn as_const(&self) -> Option<Const> {
-        // TODO: avoid clone
-        match &self.to_value() {
-            Value::Const(c) => Some(*c),
-            _ => None,
-        }
+        self.0.as_const()
     }
 
     pub fn normalize_mut(&mut self) {
-        match self {
-            Typed::Untyped(th) | Typed::Typed(th, _) => th.normalize_mut(),
-            Typed::Const(_) => {}
-        }
+        self.0.normalize_mut()
     }
 
     pub fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
-        match self {
-            Typed::Untyped(_) => Err(TypeError::new(
-                &TypecheckContext::new(),
-                TypeMessage::Untyped,
-            )),
-            Typed::Typed(_, t) => Ok(Cow::Borrowed(t)),
-            Typed::Const(c) => Ok(Cow::Owned(type_of_const(*c)?)),
-        }
+        self.0.get_type()
     }
 }
 
@@ -208,14 +177,7 @@ impl Normalized {
 
 impl Shift for Typed {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(match self {
-            Typed::Untyped(th) => Typed::Untyped(th.shift(delta, var)?),
-            Typed::Typed(th, t) => Typed::Typed(
-                th.shift(delta, var)?,
-                Box::new(t.shift(delta, var)?),
-            ),
-            Typed::Const(c) => Typed::Const(*c),
-        })
+        Some(Typed(self.0.shift(delta, var)?))
     }
 }
 
@@ -227,14 +189,7 @@ impl Shift for Normalized {
 
 impl Subst<Typed> for Typed {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        match self {
-            Typed::Untyped(th) => Typed::Untyped(th.subst_shift(var, val)),
-            Typed::Typed(th, t) => Typed::Typed(
-                th.subst_shift(var, val),
-                Box::new(t.subst_shift(var, val)),
-            ),
-            Typed::Const(c) => Typed::Const(*c),
-        }
+        Typed(self.0.subst_shift(var, val))
     }
 }
 
-- 
cgit v1.3.1


From fb0120dffe8e9552c3da7b994ad850f66dc612a3 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 13 Aug 2019 17:21:54 +0200
Subject: s/TypeThunk/TypedThunk/g

---
 dhall/src/core/thunk.rs      | 68 +++++++++++++++++++++++---------------------
 dhall/src/core/value.rs      | 24 ++++++++--------
 dhall/src/phase/mod.rs       | 16 +++++------
 dhall/src/phase/normalize.rs | 34 +++++++++++-----------
 dhall/src/phase/typecheck.rs | 40 +++++++++++++++-----------
 serde_dhall/src/lib.rs       |  6 ++--
 6 files changed, 99 insertions(+), 89 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 740ecbc..38c54f7 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -45,7 +45,7 @@ pub struct Thunk(Rc<RefCell<ThunkInternal>>);
 /// A thunk in type position. Can optionally store a Type from the typechecking phase to preserve
 /// type information through the normalization phase.
 #[derive(Debug, Clone)]
-pub enum TypeThunk {
+pub enum TypedThunk {
     // Any value, along with (optionally) its type
     Untyped(Thunk),
     Typed(Thunk, Box<Type>),
@@ -196,23 +196,23 @@ impl Thunk {
     }
 }
 
-impl TypeThunk {
-    pub fn from_value(v: Value) -> TypeThunk {
-        TypeThunk::from_thunk(Thunk::from_value(v))
+impl TypedThunk {
+    pub fn from_value(v: Value) -> TypedThunk {
+        TypedThunk::from_thunk(Thunk::from_value(v))
     }
 
-    pub fn from_thunk(th: Thunk) -> TypeThunk {
-        TypeThunk::from_thunk_untyped(th)
+    pub fn from_thunk(th: Thunk) -> TypedThunk {
+        TypedThunk::from_thunk_untyped(th)
     }
 
-    pub fn from_type(t: Type) -> TypeThunk {
+    pub fn from_type(t: Type) -> TypedThunk {
         t.into_typethunk()
     }
 
     pub fn normalize_nf(&self) -> Value {
         match self {
-            TypeThunk::Const(c) => Value::Const(*c),
-            TypeThunk::Untyped(thunk) | TypeThunk::Typed(thunk, _) => {
+            TypedThunk::Const(c) => Value::Const(*c),
+            TypedThunk::Untyped(thunk) | TypedThunk::Typed(thunk, _) => {
                 thunk.normalize_nf().clone()
             }
         }
@@ -227,23 +227,23 @@ impl TypeThunk {
     }
 
     pub fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
-        TypeThunk::Typed(th, Box::new(t))
+        TypedThunk::Typed(th, Box::new(t))
     }
     pub fn from_thunk_untyped(th: Thunk) -> Self {
-        TypeThunk::Untyped(th)
+        TypedThunk::Untyped(th)
     }
     pub fn from_const(c: Const) -> Self {
-        TypeThunk::Const(c)
+        TypedThunk::Const(c)
     }
     pub fn from_value_untyped(v: Value) -> Self {
-        TypeThunk::from_thunk_untyped(Thunk::from_value(v))
+        TypedThunk::from_thunk_untyped(Thunk::from_value(v))
     }
 
     // TODO: Avoid cloning if possible
     pub fn to_value(&self) -> Value {
         match self {
-            TypeThunk::Untyped(th) | TypeThunk::Typed(th, _) => th.to_value(),
-            TypeThunk::Const(c) => Value::Const(*c),
+            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.to_value(),
+            TypedThunk::Const(c) => Value::Const(*c),
         }
     }
     pub fn to_expr(&self) -> NormalizedSubExpr {
@@ -254,8 +254,8 @@ impl TypeThunk {
     }
     pub fn to_thunk(&self) -> Thunk {
         match self {
-            TypeThunk::Untyped(th) | TypeThunk::Typed(th, _) => th.clone(),
-            TypeThunk::Const(c) => Thunk::from_value(Value::Const(*c)),
+            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.clone(),
+            TypedThunk::Const(c) => Thunk::from_value(Value::Const(*c)),
         }
     }
     pub fn to_type(&self) -> Type {
@@ -274,21 +274,21 @@ impl TypeThunk {
 
     pub fn normalize_mut(&mut self) {
         match self {
-            TypeThunk::Untyped(th) | TypeThunk::Typed(th, _) => {
+            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => {
                 th.normalize_mut()
             }
-            TypeThunk::Const(_) => {}
+            TypedThunk::Const(_) => {}
         }
     }
 
     pub fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
         match self {
-            TypeThunk::Untyped(_) => Err(TypeError::new(
+            TypedThunk::Untyped(_) => Err(TypeError::new(
                 &TypecheckContext::new(),
                 TypeMessage::Untyped,
             )),
-            TypeThunk::Typed(_, t) => Ok(Cow::Borrowed(t)),
-            TypeThunk::Const(c) => Ok(Cow::Owned(type_of_const(*c)?)),
+            TypedThunk::Typed(_, t) => Ok(Cow::Borrowed(t)),
+            TypedThunk::Const(c) => Ok(Cow::Owned(type_of_const(*c)?)),
         }
     }
 }
@@ -319,15 +319,17 @@ impl Shift for ThunkInternal {
     }
 }
 
-impl Shift for TypeThunk {
+impl Shift for TypedThunk {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
-            TypeThunk::Untyped(th) => TypeThunk::Untyped(th.shift(delta, var)?),
-            TypeThunk::Typed(th, t) => TypeThunk::Typed(
+            TypedThunk::Untyped(th) => {
+                TypedThunk::Untyped(th.shift(delta, var)?)
+            }
+            TypedThunk::Typed(th, t) => TypedThunk::Typed(
                 th.shift(delta, var)?,
                 Box::new(t.shift(delta, var)?),
             ),
-            TypeThunk::Const(c) => TypeThunk::Const(*c),
+            TypedThunk::Const(c) => TypedThunk::Const(*c),
         })
     }
 }
@@ -365,17 +367,17 @@ impl Subst<Typed> for ThunkInternal {
     }
 }
 
-impl Subst<Typed> for TypeThunk {
+impl Subst<Typed> for TypedThunk {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
-            TypeThunk::Untyped(th) => {
-                TypeThunk::Untyped(th.subst_shift(var, val))
+            TypedThunk::Untyped(th) => {
+                TypedThunk::Untyped(th.subst_shift(var, val))
             }
-            TypeThunk::Typed(th, t) => TypeThunk::Typed(
+            TypedThunk::Typed(th, t) => TypedThunk::Typed(
                 th.subst_shift(var, val),
                 Box::new(t.subst_shift(var, val)),
             ),
-            TypeThunk::Const(c) => TypeThunk::Const(*c),
+            TypedThunk::Const(c) => TypedThunk::Const(*c),
         }
     }
 }
@@ -387,9 +389,9 @@ impl std::cmp::PartialEq for Thunk {
 }
 impl std::cmp::Eq for Thunk {}
 
-impl std::cmp::PartialEq for TypeThunk {
+impl std::cmp::PartialEq for TypedThunk {
     fn eq(&self, other: &Self) -> bool {
         self.to_value() == other.to_value()
     }
 }
-impl std::cmp::Eq for TypeThunk {}
+impl std::cmp::Eq for TypedThunk {}
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 0b68bf6..8486d6e 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble, Natural, X,
 };
 
-use crate::core::thunk::{Thunk, TypeThunk};
+use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::normalize::{
     apply_builtin, normalize_one_layer, squash_textlit, OutputSubExpr,
@@ -26,15 +26,15 @@ use crate::phase::Typed;
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Value {
     /// Closures
-    Lam(AlphaLabel, TypeThunk, Thunk),
-    Pi(AlphaLabel, TypeThunk, TypeThunk),
+    Lam(AlphaLabel, TypedThunk, Thunk),
+    Pi(AlphaLabel, TypedThunk, TypedThunk),
     // Invariant: the evaluation must not be able to progress further.
     AppliedBuiltin(Builtin, Vec<Thunk>),
     /// `λ(x: a) -> Some x`
-    OptionalSomeClosure(TypeThunk),
+    OptionalSomeClosure(TypedThunk),
     /// `λ(x : a) -> λ(xs : List a) -> [ x ] # xs`
     /// `λ(xs : List a) -> [ x ] # xs`
-    ListConsClosure(TypeThunk, Option<Thunk>),
+    ListConsClosure(TypedThunk, Option<Thunk>),
     /// `λ(x : Natural) -> x + 1`
     NaturalSuccClosure,
 
@@ -44,20 +44,20 @@ pub enum Value {
     NaturalLit(Natural),
     IntegerLit(Integer),
     DoubleLit(NaiveDouble),
-    EmptyOptionalLit(TypeThunk),
+    EmptyOptionalLit(TypedThunk),
     NEOptionalLit(Thunk),
     // EmptyListLit(t) means `[] : List t`, not `[] : t`
-    EmptyListLit(TypeThunk),
+    EmptyListLit(TypedThunk),
     NEListLit(Vec<Thunk>),
     RecordLit(HashMap<Label, Thunk>),
-    RecordType(HashMap<Label, TypeThunk>),
-    UnionType(HashMap<Label, Option<TypeThunk>>),
-    UnionConstructor(Label, HashMap<Label, Option<TypeThunk>>),
-    UnionLit(Label, Thunk, HashMap<Label, Option<TypeThunk>>),
+    RecordType(HashMap<Label, TypedThunk>),
+    UnionType(HashMap<Label, Option<TypedThunk>>),
+    UnionConstructor(Label, HashMap<Label, Option<TypedThunk>>),
+    UnionLit(Label, Thunk, HashMap<Label, Option<TypedThunk>>),
     // Invariant: this must not contain interpolations that are themselves TextLits, and
     // contiguous text values must be merged.
     TextLit(Vec<InterpolatedTextContents<Thunk>>),
-    Equivalence(TypeThunk, TypeThunk),
+    Equivalence(TypedThunk, TypedThunk),
     // Invariant: this must not contain a value captured by one of the variants above.
     PartialExpr(ExprF<Thunk, X>),
 }
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 0b05227..27a6901 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -4,7 +4,7 @@ use std::path::Path;
 
 use dhall_syntax::{Const, Import, Span, SubExpr, X};
 
-use crate::core::thunk::{Thunk, TypeThunk};
+use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{EncodeError, Error, ImportError, TypeError};
@@ -31,7 +31,7 @@ pub struct Resolved(ResolvedSubExpr);
 
 /// A typed expression
 #[derive(Debug, Clone)]
-pub struct Typed(TypeThunk);
+pub struct Typed(TypedThunk);
 
 /// A normalized expression.
 ///
@@ -100,18 +100,18 @@ impl Typed {
     }
 
     pub fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
-        Typed(TypeThunk::from_thunk_and_type(th, t))
+        Typed(TypedThunk::from_thunk_and_type(th, t))
     }
     pub fn from_thunk_untyped(th: Thunk) -> Self {
-        Typed(TypeThunk::from_thunk_untyped(th))
+        Typed(TypedThunk::from_thunk_untyped(th))
     }
     pub fn from_const(c: Const) -> Self {
-        Typed(TypeThunk::from_const(c))
+        Typed(TypedThunk::from_const(c))
     }
     pub fn from_value_untyped(v: Value) -> Self {
-        Typed(TypeThunk::from_value_untyped(v))
+        Typed(TypedThunk::from_value_untyped(v))
     }
-    pub fn from_typethunk(th: TypeThunk) -> Self {
+    pub fn from_typethunk(th: TypedThunk) -> Self {
         Typed(th)
     }
 
@@ -135,7 +135,7 @@ impl Typed {
     pub fn into_type(self) -> Type {
         self
     }
-    pub fn into_typethunk(self) -> TypeThunk {
+    pub fn into_typethunk(self) -> TypedThunk {
         self.0
     }
     pub fn to_normalized(&self) -> Normalized {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 405677a..644f98c 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -6,7 +6,7 @@ use dhall_syntax::{
 };
 
 use crate::core::context::NormalizationContext;
-use crate::core::thunk::{Thunk, TypeThunk};
+use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
 use crate::core::var::Subst;
 use crate::phase::{NormalizedSubExpr, ResolvedSubExpr, Typed};
@@ -22,7 +22,7 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
     // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
     let ret = match (b, args.as_slice()) {
         (OptionalNone, [t, r..]) => {
-            Ok((r, EmptyOptionalLit(TypeThunk::from_thunk(t.clone()))))
+            Ok((r, EmptyOptionalLit(TypedThunk::from_thunk(t.clone()))))
         }
         (NaturalIsZero, [n, r..]) => match &*n.as_value() {
             NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
@@ -144,10 +144,10 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                 let mut kts = HashMap::new();
                 kts.insert(
                     "index".into(),
-                    TypeThunk::from_value(Value::from_builtin(Natural)),
+                    TypedThunk::from_value(Value::from_builtin(Natural)),
                 );
                 kts.insert("value".into(), t.clone());
-                Ok((r, EmptyListLit(TypeThunk::from_value(RecordType(kts)))))
+                Ok((r, EmptyListLit(TypedThunk::from_value(RecordType(kts)))))
             }
             NEListLit(xs) => {
                 let xs = xs
@@ -179,10 +179,10 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                 r,
                 f.app_val(Value::from_builtin(List).app_thunk(t.clone()))
                     .app_val(ListConsClosure(
-                        TypeThunk::from_thunk(t.clone()),
+                        TypedThunk::from_thunk(t.clone()),
                         None,
                     ))
-                    .app_val(EmptyListLit(TypeThunk::from_thunk(t.clone()))),
+                    .app_val(EmptyListLit(TypedThunk::from_thunk(t.clone()))),
             )),
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_value() {
@@ -213,10 +213,10 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             _ => Ok((
                 r,
                 f.app_val(Value::from_builtin(Optional).app_thunk(t.clone()))
-                    .app_val(OptionalSomeClosure(TypeThunk::from_thunk(
+                    .app_val(OptionalSomeClosure(TypedThunk::from_thunk(
                         t.clone(),
                     )))
-                    .app_val(EmptyOptionalLit(TypeThunk::from_thunk(
+                    .app_val(EmptyOptionalLit(TypedThunk::from_thunk(
                         t.clone(),
                     ))),
             )),
@@ -618,7 +618,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         }
         (RecursiveRecordTypeMerge, RecordType(kvs1), RecordType(kvs2)) => {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
-                TypeThunk::from_thunk(Thunk::from_partial_expr(ExprF::BinOp(
+                TypedThunk::from_thunk(Thunk::from_partial_expr(ExprF::BinOp(
                     RecursiveRecordTypeMerge,
                     v1.to_thunk(),
                     v2.to_thunk(),
@@ -628,8 +628,8 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         }
 
         (Equivalence, _, _) => Ret::Value(Value::Equivalence(
-            TypeThunk::from_thunk(x.clone()),
-            TypeThunk::from_thunk(y.clone()),
+            TypedThunk::from_thunk(x.clone()),
+            TypedThunk::from_thunk(y.clone()),
         )),
 
         _ => return None,
@@ -649,12 +649,12 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value {
         ExprF::Annot(x, _) => Ret::Thunk(x),
         ExprF::Assert(_) => Ret::Expr(expr),
         ExprF::Lam(x, t, e) => {
-            Ret::Value(Lam(x.into(), TypeThunk::from_thunk(t), e))
+            Ret::Value(Lam(x.into(), TypedThunk::from_thunk(t), e))
         }
         ExprF::Pi(x, t, e) => Ret::Value(Pi(
             x.into(),
-            TypeThunk::from_thunk(t),
-            TypeThunk::from_thunk(e),
+            TypedThunk::from_thunk(t),
+            TypedThunk::from_thunk(e),
         )),
         ExprF::Let(x, _, v, b) => {
             let v = Typed::from_thunk_untyped(v);
@@ -673,7 +673,7 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value {
             let t_borrow = t.as_value();
             match &*t_borrow {
                 AppliedBuiltin(Builtin::List, args) if args.len() == 1 => {
-                    Ret::Value(EmptyListLit(TypeThunk::from_thunk(
+                    Ret::Value(EmptyListLit(TypedThunk::from_thunk(
                         args[0].clone(),
                     )))
                 }
@@ -691,12 +691,12 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value {
         }
         ExprF::RecordType(kts) => Ret::Value(RecordType(
             kts.into_iter()
-                .map(|(k, t)| (k, TypeThunk::from_thunk(t)))
+                .map(|(k, t)| (k, TypedThunk::from_thunk(t)))
                 .collect(),
         )),
         ExprF::UnionType(kts) => Ret::Value(UnionType(
             kts.into_iter()
-                .map(|(k, t)| (k, t.map(|t| TypeThunk::from_thunk(t))))
+                .map(|(k, t)| (k, t.map(|t| TypedThunk::from_thunk(t))))
                 .collect(),
         )),
         ExprF::TextLit(elts) => {
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 299997a..a19e1ca 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -6,7 +6,7 @@ use dhall_syntax::{
 };
 
 use crate::core::context::{NormalizationContext, TypecheckContext};
-use crate::core::thunk::{Thunk, TypeThunk};
+use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
 use crate::core::var::{Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
@@ -44,8 +44,12 @@ fn tck_pi_type(
     let k = function_check(ka, kb);
 
     Ok(Typed::from_thunk_and_type(
-        Value::Pi(x.into(), TypeThunk::from_type(tx), TypeThunk::from_type(te))
-            .into_thunk(),
+        Value::Pi(
+            x.into(),
+            TypedThunk::from_type(tx),
+            TypedThunk::from_type(te),
+        )
+        .into_thunk(),
         Type::from_const(k),
     ))
 }
@@ -77,7 +81,7 @@ fn tck_record_type(
                 return Err(TypeError::new(ctx, RecordTypeDuplicateField))
             }
             Entry::Vacant(_) => {
-                entry.or_insert_with(|| TypeThunk::from_type(t.clone()))
+                entry.or_insert_with(|| TypedThunk::from_type(t.clone()))
             }
         };
     }
@@ -119,7 +123,7 @@ fn tck_union_type(
                 return Err(TypeError::new(ctx, UnionTypeDuplicateField))
             }
             Entry::Vacant(_) => entry.or_insert_with(|| {
-                t.as_ref().map(|t| TypeThunk::from_type(t.clone()))
+                t.as_ref().map(|t| TypedThunk::from_type(t.clone()))
             }),
         };
     }
@@ -334,7 +338,7 @@ fn type_with(
             let b = type_with(&ctx2, b.clone())?;
             let v = Value::Lam(
                 x.clone().into(),
-                TypeThunk::from_type(tx.clone()),
+                TypedThunk::from_type(tx.clone()),
                 b.to_thunk(),
             );
             let tb = b.get_type()?.into_owned();
@@ -658,8 +662,8 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: HashMap<Label, TypeThunk>,
-                kts_r: HashMap<Label, TypeThunk>,
+                kts_l: HashMap<Label, TypedThunk>,
+                kts_r: HashMap<Label, TypedThunk>,
             ) -> Result<Typed, TypeError> {
                 use crate::phase::normalize::outer_join;
 
@@ -667,8 +671,8 @@ fn type_last_layer(
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
                 let combine = |k: &Label,
-                               inner_l: &TypeThunk,
-                               inner_r: &TypeThunk|
+                               inner_l: &TypedThunk,
+                               inner_r: &TypedThunk|
                  -> Result<Typed, TypeError> {
                     match (inner_l.to_value(), inner_r.to_value()) {
                         (
@@ -686,7 +690,9 @@ fn type_last_layer(
                 let kts: HashMap<Label, Result<Typed, TypeError>> = outer_join(
                     |l| Ok(l.to_type()),
                     |r| Ok(r.to_type()),
-                    |k: &Label, l: &TypeThunk, r: &TypeThunk| combine(k, l, r),
+                    |k: &Label, l: &TypedThunk, r: &TypedThunk| {
+                        combine(k, l, r)
+                    },
                     &kts_l,
                     &kts_r,
                 );
@@ -729,8 +735,8 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: HashMap<Label, TypeThunk>,
-                kts_r: HashMap<Label, TypeThunk>,
+                kts_l: HashMap<Label, TypedThunk>,
+                kts_r: HashMap<Label, TypedThunk>,
             ) -> Result<Typed, TypeError> {
                 use crate::phase::normalize::intersection_with_key;
 
@@ -738,8 +744,8 @@ fn type_last_layer(
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
                 let combine = |k: &Label,
-                               kts_l_inner: &TypeThunk,
-                               kts_r_inner: &TypeThunk|
+                               kts_l_inner: &TypedThunk,
+                               kts_r_inner: &TypedThunk|
                  -> Result<Typed, TypeError> {
                     match (kts_l_inner.to_value(), kts_r_inner.to_value()) {
                         (
@@ -755,7 +761,9 @@ fn type_last_layer(
                 };
 
                 let kts = intersection_with_key(
-                    |k: &Label, l: &TypeThunk, r: &TypeThunk| combine(k, l, r),
+                    |k: &Label, l: &TypedThunk, r: &TypedThunk| {
+                        combine(k, l, r)
+                    },
                     &kts_l,
                     &kts_r,
                 );
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 19aabec..14d8b47 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -124,7 +124,7 @@ pub use value::Value;
 
 // A Dhall value.
 pub mod value {
-    use dhall::core::thunk::{Thunk, TypeThunk};
+    use dhall::core::thunk::{Thunk, TypedThunk};
     use dhall::core::value::Value as DhallValue;
     use dhall::phase::{NormalizedSubExpr, Parsed, Type, Typed};
     use dhall_syntax::Builtin;
@@ -185,7 +185,7 @@ pub mod value {
         ) -> Self {
             Self::from_dhall_value(DhallValue::RecordType(
                 kts.map(|(k, t)| {
-                    (k.into(), TypeThunk::from_thunk(t.to_thunk()))
+                    (k.into(), TypedThunk::from_thunk(t.to_thunk()))
                 })
                 .collect(),
             ))
@@ -196,7 +196,7 @@ pub mod value {
         ) -> Self {
             Self::from_dhall_value(DhallValue::UnionType(
                 kts.map(|(k, t)| {
-                    (k.into(), t.map(|t| TypeThunk::from_thunk(t.to_thunk())))
+                    (k.into(), t.map(|t| TypedThunk::from_thunk(t.to_thunk())))
                 })
                 .collect(),
             ))
-- 
cgit v1.3.1


From cbd62bb57bcc94e0133c57437488a5af22a0b1c2 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 13 Aug 2019 17:34:38 +0200
Subject: Typos

---
 dhall/src/core/thunk.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 38c54f7..c18014e 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -49,9 +49,9 @@ pub enum TypedThunk {
     // Any value, along with (optionally) its type
     Untyped(Thunk),
     Typed(Thunk, Box<Type>),
-    // One of the base higher-kinded typed.
+    // One of the base higher-kinded types.
     // Used to avoid storing the same tower ot Type->Kind->Sort
-    // over and over again. Also enables having Sort as a type
+    // over and over again. Also enables having Sort as a value
     // even though it doesn't itself have a type.
     Const(Const),
 }
-- 
cgit v1.3.1


From 77af0bbc171618f48531cc6b1d77e18089928885 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 13 Aug 2019 20:54:15 +0200
Subject: Stop tracking the absence of Embed values at the type level

---
 dhall/src/core/thunk.rs          | 12 ++++++------
 dhall/src/core/value.rs          | 10 +++++-----
 dhall/src/phase/mod.rs           |  4 ++--
 dhall/src/phase/normalize.rs     | 21 +++++++++++----------
 dhall/src/phase/typecheck.rs     | 11 ++++-------
 dhall_syntax/src/core/context.rs |  2 +-
 dhall_syntax/src/core/expr.rs    | 16 ++--------------
 dhall_syntax/src/core/visitor.rs | 15 +--------------
 dhall_syntax/src/printer.rs      |  6 ------
 9 files changed, 32 insertions(+), 65 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index c18014e..4d193f9 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::cell::{Ref, RefCell};
 use std::rc::Rc;
 
-use dhall_syntax::{Const, ExprF, X};
+use dhall_syntax::{Const, ExprF};
 
 use crate::core::context::{NormalizationContext, TypecheckContext};
 use crate::core::value::Value;
@@ -12,7 +12,7 @@ use crate::phase::normalize::{
     apply_any, normalize_one_layer, normalize_whnf, InputSubExpr, OutputSubExpr,
 };
 use crate::phase::typecheck::type_of_const;
-use crate::phase::{NormalizedSubExpr, Type, Typed};
+use crate::phase::{Normalized, NormalizedSubExpr, Type, Typed};
 
 #[derive(Debug, Clone, Copy)]
 enum Marker {
@@ -30,7 +30,7 @@ enum ThunkInternal {
     /// Partially normalized value whose subexpressions have been thunked (this is returned from
     /// typechecking). Note that this is different from `Value::PartialExpr` because there is no
     /// requirement of WHNF here.
-    PartialExpr(ExprF<Thunk, X>),
+    PartialExpr(ExprF<Thunk, Normalized>),
     /// Partially normalized value.
     /// Invariant: if the marker is `NF`, the value must be fully normalized
     Value(Marker, Value),
@@ -123,7 +123,7 @@ impl Thunk {
         ThunkInternal::Value(WHNF, v).into_thunk()
     }
 
-    pub fn from_partial_expr(e: ExprF<Thunk, X>) -> Thunk {
+    pub fn from_partial_expr(e: ExprF<Thunk, Normalized>) -> Thunk {
         ThunkInternal::PartialExpr(e).into_thunk()
     }
 
@@ -309,7 +309,7 @@ impl Shift for ThunkInternal {
                 e.traverse_ref_with_special_handling_of_binders(
                     |v| Ok(v.shift(delta, var)?),
                     |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
-                    |x| Ok(X::clone(x)),
+                    |x| Ok(Normalized::clone(x)),
                 )?,
             ),
             ThunkInternal::Value(m, v) => {
@@ -356,7 +356,7 @@ impl Subst<Typed> for ThunkInternal {
                             &val.under_binder(x),
                         )
                     },
-                    X::clone,
+                    Normalized::clone,
                 ),
             ),
             ThunkInternal::Value(_, v) => {
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 8486d6e..88d7a20 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -2,7 +2,7 @@ use std::collections::HashMap;
 
 use dhall_syntax::{
     rc, Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label,
-    NaiveDouble, Natural, X,
+    NaiveDouble, Natural,
 };
 
 use crate::core::thunk::{Thunk, TypedThunk};
@@ -10,7 +10,7 @@ use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::normalize::{
     apply_builtin, normalize_one_layer, squash_textlit, OutputSubExpr,
 };
-use crate::phase::Typed;
+use crate::phase::{Normalized, Typed};
 
 /// A semantic value. The invariants ensure this value represents a Weak-Head
 /// Normal Form (WHNF). This means that this first constructor is the first constructor of the
@@ -59,7 +59,7 @@ pub enum Value {
     TextLit(Vec<InterpolatedTextContents<Thunk>>),
     Equivalence(TypedThunk, TypedThunk),
     // Invariant: this must not contain a value captured by one of the variants above.
-    PartialExpr(ExprF<Thunk, X>),
+    PartialExpr(ExprF<Thunk, Normalized>),
 }
 
 impl Value {
@@ -475,7 +475,7 @@ impl Shift for Value {
                 e.traverse_ref_with_special_handling_of_binders(
                     |v| Ok(v.shift(delta, var)?),
                     |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
-                    |x| Ok(X::clone(x)),
+                    |x| Ok(Normalized::clone(x)),
                 )?,
             ),
         })
@@ -500,7 +500,7 @@ impl Subst<Typed> for Value {
                             &val.under_binder(x),
                         )
                     },
-                    X::clone,
+                    Normalized::clone,
                 ))
             }
             // Retry normalizing since substituting may allow progress
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 8c93889..7364949 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::fmt::Display;
 use std::path::Path;
 
-use dhall_syntax::{Const, Import, SubExpr, X};
+use dhall_syntax::{Const, Import, SubExpr};
 
 use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
@@ -20,7 +20,7 @@ pub(crate) mod typecheck;
 pub type ParsedSubExpr = SubExpr<Import>;
 pub type DecodedSubExpr = SubExpr<Import>;
 pub type ResolvedSubExpr = SubExpr<Normalized>;
-pub type NormalizedSubExpr = SubExpr<X>;
+pub type NormalizedSubExpr = SubExpr<Normalized>;
 
 #[derive(Debug, Clone)]
 pub struct Parsed(ParsedSubExpr, ImportRoot);
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 644f98c..f1045a5 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -2,14 +2,14 @@ use std::collections::HashMap;
 
 use dhall_syntax::{
     BinOp, Builtin, ExprF, InterpolatedText, InterpolatedTextContents,
-    NaiveDouble, X,
+    NaiveDouble,
 };
 
 use crate::core::context::NormalizationContext;
 use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
 use crate::core::var::Subst;
-use crate::phase::{NormalizedSubExpr, ResolvedSubExpr, Typed};
+use crate::phase::{Normalized, NormalizedSubExpr, ResolvedSubExpr, Typed};
 
 pub type InputSubExpr = ResolvedSubExpr;
 pub type OutputSubExpr = NormalizedSubExpr;
@@ -86,7 +86,7 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                     // Empty string literal.
                     [] => {
                         // Printing InterpolatedText takes care of all the escaping
-                        let txt: InterpolatedText<X> =
+                        let txt: InterpolatedText<Normalized> =
                             std::iter::empty().collect();
                         let s = txt.to_string();
                         Ok((
@@ -98,10 +98,11 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                     // interpolations, there is a single Text item) in the literal.
                     [InterpolatedTextContents::Text(s)] => {
                         // Printing InterpolatedText takes care of all the escaping
-                        let txt: InterpolatedText<X> = std::iter::once(
-                            InterpolatedTextContents::Text(s.clone()),
-                        )
-                        .collect();
+                        let txt: InterpolatedText<Normalized> =
+                            std::iter::once(InterpolatedTextContents::Text(
+                                s.clone(),
+                            ))
+                            .collect();
                         let s = txt.to_string();
                         Ok((
                             r,
@@ -376,7 +377,7 @@ pub fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
     }
 
     // Thunk subexpressions
-    let expr: ExprF<Thunk, X> =
+    let expr: ExprF<Thunk, Normalized> =
         expr.as_ref().map_ref_with_special_handling_of_binders(
             |e| Thunk::new(ctx.clone(), e.clone()),
             |x, e| Thunk::new(ctx.skip(x), e.clone()),
@@ -391,7 +392,7 @@ enum Ret<'a> {
     Value(Value),
     Thunk(Thunk),
     ThunkRef(&'a Thunk),
-    Expr(ExprF<Thunk, X>),
+    Expr(ExprF<Thunk, Normalized>),
 }
 
 /// Performs an intersection of two HashMaps.
@@ -636,7 +637,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
     })
 }
 
-pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value {
+pub fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
     use Value::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, Lam,
         NEListLit, NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType,
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index ecf9793..96ff246 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -2,7 +2,6 @@ use std::collections::HashMap;
 
 use dhall_syntax::{
     rc, Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label, SubExpr,
-    X,
 };
 
 use crate::core::context::{NormalizationContext, TypecheckContext};
@@ -214,7 +213,7 @@ macro_rules! make_type {
     };
 }
 
-fn type_of_builtin(b: Builtin) -> Expr<X> {
+fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
     use dhall_syntax::Builtin::*;
     match b {
         Bool | Natural | Integer | Double | Text => make_type!(Type),
@@ -398,7 +397,7 @@ fn type_with(
 /// layer.
 fn type_last_layer(
     ctx: &TypecheckContext,
-    e: &ExprF<Typed, X>,
+    e: &ExprF<Typed, Normalized>,
 ) -> Result<Ret, TypeError> {
     use crate::error::TypeMessage::*;
     use dhall_syntax::BinOp::*;
@@ -598,9 +597,7 @@ fn type_last_layer(
             }
         }
         Const(c) => Ok(RetWhole(Typed::from_const(*c))),
-        Builtin(b) => {
-            Ok(RetTypeOnly(mktype(ctx, rc(type_of_builtin(*b)).absurd())?))
-        }
+        Builtin(b) => Ok(RetTypeOnly(mktype(ctx, rc(type_of_builtin(*b)))?)),
         BoolLit(_) => Ok(RetTypeOnly(builtin_to_type(Bool)?)),
         NaturalLit(_) => Ok(RetTypeOnly(builtin_to_type(Natural)?)),
         IntegerLit(_) => Ok(RetTypeOnly(builtin_to_type(Integer)?)),
@@ -1016,7 +1013,7 @@ pub fn typecheck(e: Resolved) -> Result<Typed, TypeError> {
 
 pub fn typecheck_with(e: Resolved, ty: &Type) -> Result<Typed, TypeError> {
     let expr: SubExpr<_> = e.0;
-    let ty: SubExpr<_> = ty.to_expr().absurd();
+    let ty: SubExpr<_> = ty.to_expr();
     type_of(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
 }
 pub fn skip_typecheck(e: Resolved) -> Typed {
diff --git a/dhall_syntax/src/core/context.rs b/dhall_syntax/src/core/context.rs
index eeec121..6844baa 100644
--- a/dhall_syntax/src/core/context.rs
+++ b/dhall_syntax/src/core/context.rs
@@ -4,7 +4,7 @@ use std::hash::Hash;
 
 /// A `(Context a)` associates `Text` labels with values of type `a`
 ///
-/// The `Context` is used for type-checking when `(a = Expr X)`
+/// The `Context` is used for type-checking when `(a = Expr)`
 ///
 /// * You create a `Context` using `empty` and `insert`
 /// * You transform a `Context` using `fmap`
diff --git a/dhall_syntax/src/core/expr.rs b/dhall_syntax/src/core/expr.rs
index 0cbece3..e08d816 100644
--- a/dhall_syntax/src/core/expr.rs
+++ b/dhall_syntax/src/core/expr.rs
@@ -10,9 +10,9 @@ pub type Double = NaiveDouble;
 
 /// An empty type
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum X {}
+pub enum Void {}
 
-pub fn trivial_result<T>(x: Result<T, X>) -> T {
+pub fn trivial_result<T>(x: Result<T, Void>) -> T {
     match x {
         Ok(x) => x,
         Err(e) => match e {},
@@ -351,12 +351,6 @@ impl<E> Expr<E> {
     }
 }
 
-impl Expr<X> {
-    pub fn absurd<E>(&self) -> Expr<E> {
-        self.visit(&mut visitor::AbsurdVisitor)
-    }
-}
-
 impl<E> SubExpr<E> {
     pub fn as_ref(&self) -> &Expr<E> {
         &self.0.as_ref().0
@@ -416,12 +410,6 @@ impl<E> SubExpr<E> {
     }
 }
 
-impl SubExpr<X> {
-    pub fn absurd<T>(&self) -> SubExpr<T> {
-        SubExpr::from_expr_no_span(self.as_ref().absurd())
-    }
-}
-
 impl<E> Clone for SubExpr<E> {
     fn clone(&self) -> Self {
         SubExpr(Rc::clone(&self.0))
diff --git a/dhall_syntax/src/core/visitor.rs b/dhall_syntax/src/core/visitor.rs
index 50ec68a..e39e95b 100644
--- a/dhall_syntax/src/core/visitor.rs
+++ b/dhall_syntax/src/core/visitor.rs
@@ -243,7 +243,7 @@ impl<'a, T, SE1, SE2, E1, E2> ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>
 where
     T: ExprFInFallibleVisitor<'a, SE1, SE2, E1, E2>,
 {
-    type Error = X;
+    type Error = Void;
 
     fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error> {
         Ok(self.0.visit_subexpr(subexpr))
@@ -379,16 +379,3 @@ where
         (self.0)(embed)
     }
 }
-
-pub struct AbsurdVisitor;
-
-impl<'a, 'b, E> ExprFInFallibleVisitor<'a, SubExpr<X>, SubExpr<E>, X, E>
-    for &'b mut AbsurdVisitor
-{
-    fn visit_subexpr(&mut self, subexpr: &'a SubExpr<X>) -> SubExpr<E> {
-        SubExpr::from_expr_no_span(subexpr.as_ref().visit(&mut **self))
-    }
-    fn visit_embed(self, embed: &'a X) -> E {
-        match *embed {}
-    }
-}
diff --git a/dhall_syntax/src/printer.rs b/dhall_syntax/src/printer.rs
index 95eafe5..25d4ca8 100644
--- a/dhall_syntax/src/printer.rs
+++ b/dhall_syntax/src/printer.rs
@@ -491,9 +491,3 @@ impl<Label: Display> Display for V<Label> {
         Ok(())
     }
 }
-
-impl Display for X {
-    fn fmt(&self, _: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        match *self {}
-    }
-}
-- 
cgit v1.3.1


From 51dbaa0b66089bca63aa9cf69a1e0ec59df053b9 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 13 Aug 2019 21:10:59 +0200
Subject: Considerably simplify Embed handling

---
 dhall/src/core/thunk.rs          |   2 -
 dhall/src/core/value.rs          |   8 ++-
 dhall/src/phase/normalize.rs     |   1 -
 dhall/src/phase/typecheck.rs     |   3 +-
 dhall_syntax/src/core/expr.rs    | 110 +++++++++------------------------------
 dhall_syntax/src/core/visitor.rs |  60 ++++++---------------
 dhall_syntax/src/printer.rs      |   2 +-
 7 files changed, 48 insertions(+), 138 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 4d193f9..7c5c537 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -309,7 +309,6 @@ impl Shift for ThunkInternal {
                 e.traverse_ref_with_special_handling_of_binders(
                     |v| Ok(v.shift(delta, var)?),
                     |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
-                    |x| Ok(Normalized::clone(x)),
                 )?,
             ),
             ThunkInternal::Value(m, v) => {
@@ -356,7 +355,6 @@ impl Subst<Typed> for ThunkInternal {
                             &val.under_binder(x),
                         )
                     },
-                    Normalized::clone,
                 ),
             ),
             ThunkInternal::Value(_, v) => {
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 88d7a20..20a6021 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -243,7 +243,7 @@ impl Value {
                 y.normalize_to_expr_maybe_alpha(alpha),
             )),
             Value::PartialExpr(e) => {
-                rc(e.map_ref_simple(|v| v.normalize_to_expr_maybe_alpha(alpha)))
+                rc(e.map_ref(|v| v.normalize_to_expr_maybe_alpha(alpha)))
             }
         }
     }
@@ -333,8 +333,8 @@ impl Value {
                 y.normalize_mut();
             }
             Value::PartialExpr(e) => {
-                // TODO: need map_mut_simple
-                e.map_ref_simple(|v| {
+                // TODO: need map_mut
+                e.map_ref(|v| {
                     v.normalize_nf();
                 });
             }
@@ -475,7 +475,6 @@ impl Shift for Value {
                 e.traverse_ref_with_special_handling_of_binders(
                     |v| Ok(v.shift(delta, var)?),
                     |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
-                    |x| Ok(Normalized::clone(x)),
                 )?,
             ),
         })
@@ -500,7 +499,6 @@ impl Subst<Typed> for Value {
                             &val.under_binder(x),
                         )
                     },
-                    Normalized::clone,
                 ))
             }
             // Retry normalizing since substituting may allow progress
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index f1045a5..2970f5f 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -381,7 +381,6 @@ pub fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
         expr.as_ref().map_ref_with_special_handling_of_binders(
             |e| Thunk::new(ctx.clone(), e.clone()),
             |x, e| Thunk::new(ctx.skip(x), e.clone()),
-            |_| unreachable!(),
         );
 
     normalize_one_layer(expr)
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 96ff246..e8b2544 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -376,12 +376,11 @@ fn type_with(
                 e.as_ref().traverse_ref_with_special_handling_of_binders(
                     |e| type_with(ctx, e.clone()),
                     |_, _| unreachable!(),
-                    |_| unreachable!(),
                 )?;
             let ret = type_last_layer(ctx, &expr)?;
             match ret {
                 RetTypeOnly(typ) => {
-                    let expr = expr.map_ref_simple(|typed| typed.to_thunk());
+                    let expr = expr.map_ref(|typed| typed.to_thunk());
                     Typed::from_thunk_and_type(
                         Thunk::from_partial_expr(expr),
                         typ,
diff --git a/dhall_syntax/src/core/expr.rs b/dhall_syntax/src/core/expr.rs
index e08d816..74eb993 100644
--- a/dhall_syntax/src/core/expr.rs
+++ b/dhall_syntax/src/core/expr.rs
@@ -245,92 +245,62 @@ impl<SE, E> ExprF<SE, E> {
         v.visit(self)
     }
 
-    pub fn traverse_ref_with_special_handling_of_binders<'a, SE2, E2, Err>(
+    pub fn traverse_ref_with_special_handling_of_binders<'a, SE2, Err>(
         &'a self,
         visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
         visit_under_binder: impl FnOnce(&'a Label, &'a SE) -> Result<SE2, Err>,
-        visit_embed: impl FnOnce(&'a E) -> Result<E2, Err>,
-    ) -> Result<ExprF<SE2, E2>, Err> {
+    ) -> Result<ExprF<SE2, E>, Err>
+    where
+        E: Clone,
+    {
         self.visit(visitor::TraverseRefWithBindersVisitor {
             visit_subexpr,
             visit_under_binder,
-            visit_embed,
         })
     }
 
-    fn traverse_ref<'a, SE2, E2, Err>(
+    fn traverse_ref<'a, SE2, Err>(
         &'a self,
         visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
-        visit_embed: impl FnOnce(&'a E) -> Result<E2, Err>,
-    ) -> Result<ExprF<SE2, E2>, Err> {
-        self.visit(visitor::TraverseRefVisitor {
-            visit_subexpr,
-            visit_embed,
-        })
+    ) -> Result<ExprF<SE2, E>, Err>
+    where
+        E: Clone,
+    {
+        self.visit(visitor::TraverseRefVisitor { visit_subexpr })
     }
 
-    pub fn map_ref_with_special_handling_of_binders<'a, SE2, E2>(
+    pub fn map_ref_with_special_handling_of_binders<'a, SE2>(
         &'a self,
         mut map_subexpr: impl FnMut(&'a SE) -> SE2,
         mut map_under_binder: impl FnMut(&'a Label, &'a SE) -> SE2,
-        map_embed: impl FnOnce(&'a E) -> E2,
-    ) -> ExprF<SE2, E2> {
+    ) -> ExprF<SE2, E>
+    where
+        E: Clone,
+    {
         trivial_result(self.traverse_ref_with_special_handling_of_binders(
             |x| Ok(map_subexpr(x)),
             |l, x| Ok(map_under_binder(l, x)),
-            |x| Ok(map_embed(x)),
         ))
     }
 
-    pub fn map_ref<'a, SE2, E2>(
+    pub fn map_ref<'a, SE2>(
         &'a self,
         mut map_subexpr: impl FnMut(&'a SE) -> SE2,
-        map_embed: impl FnOnce(&'a E) -> E2,
-    ) -> ExprF<SE2, E2> {
-        trivial_result(
-            self.traverse_ref(|x| Ok(map_subexpr(x)), |x| Ok(map_embed(x))),
-        )
-    }
-
-    pub fn traverse_ref_simple<'a, SE2, Err>(
-        &'a self,
-        visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
-    ) -> Result<ExprF<SE2, E>, Err>
-    where
-        E: Clone,
-    {
-        self.traverse_ref(visit_subexpr, |x| Ok(E::clone(x)))
-    }
-
-    pub fn map_ref_simple<'a, SE2>(
-        &'a self,
-        map_subexpr: impl Fn(&'a SE) -> SE2,
     ) -> ExprF<SE2, E>
     where
         E: Clone,
     {
-        self.map_ref(map_subexpr, E::clone)
+        trivial_result(self.traverse_ref(|x| Ok(map_subexpr(x))))
     }
 }
 
-impl<E> Expr<E> {
-    fn traverse_embed<E2, Err>(
-        &self,
-        visit_embed: impl FnMut(&E) -> Result<E2, Err>,
-    ) -> Result<Expr<E2>, Err> {
-        self.visit(&mut visitor::TraverseEmbedVisitor(visit_embed))
-    }
-
-    fn map_embed<E2>(&self, mut map_embed: impl FnMut(&E) -> E2) -> Expr<E2> {
-        trivial_result(self.traverse_embed(|x| Ok(map_embed(x))))
-    }
-
+impl Expr<Import> {
     pub fn traverse_resolve<E2, Err>(
         &self,
-        visit_embed: impl FnMut(&E) -> Result<E2, Err>,
+        visit_import: impl FnMut(&Import) -> Result<E2, Err>,
     ) -> Result<Expr<E2>, Err> {
         self.traverse_resolve_with_visitor(&mut visitor::ResolveVisitor(
-            visit_embed,
+            visit_import,
         ))
     }
 
@@ -339,7 +309,7 @@ impl<E> Expr<E> {
         visitor: &mut visitor::ResolveVisitor<F1>,
     ) -> Result<Expr<E2>, Err>
     where
-        F1: FnMut(&E) -> Result<E2, Err>,
+        F1: FnMut(&Import) -> Result<E2, Err>,
     {
         match self {
             ExprF::BinOp(BinOp::ImportAlt, l, r) => l
@@ -371,42 +341,14 @@ impl<E> SubExpr<E> {
     pub fn rewrap<E2>(&self, x: Expr<E2>) -> SubExpr<E2> {
         SubExpr(Rc::new((x, (self.0).1.clone())))
     }
+}
 
-    pub fn traverse_embed<E2, Err>(
-        &self,
-        visit_embed: impl FnMut(&E) -> Result<E2, Err>,
-    ) -> Result<SubExpr<E2>, Err> {
-        Ok(self.rewrap(self.as_ref().traverse_embed(visit_embed)?))
-    }
-
-    pub fn map_embed<E2>(
-        &self,
-        map_embed: impl FnMut(&E) -> E2,
-    ) -> SubExpr<E2> {
-        self.rewrap(self.as_ref().map_embed(map_embed))
-    }
-
-    pub fn map_subexprs_with_special_handling_of_binders<'a>(
-        &'a self,
-        map_expr: impl FnMut(&'a Self) -> Self,
-        map_under_binder: impl FnMut(&'a Label, &'a Self) -> Self,
-    ) -> Self {
-        match self.as_ref() {
-            ExprF::Embed(_) => SubExpr::clone(self),
-            // This calls ExprF::map_ref
-            e => self.rewrap(e.map_ref_with_special_handling_of_binders(
-                map_expr,
-                map_under_binder,
-                |_| unreachable!(),
-            )),
-        }
-    }
-
+impl SubExpr<Import> {
     pub fn traverse_resolve<E2, Err>(
         &self,
-        visit_embed: impl FnMut(&E) -> Result<E2, Err>,
+        visit_import: impl FnMut(&Import) -> Result<E2, Err>,
     ) -> Result<SubExpr<E2>, Err> {
-        Ok(self.rewrap(self.as_ref().traverse_resolve(visit_embed)?))
+        Ok(self.rewrap(self.as_ref().traverse_resolve(visit_import)?))
     }
 }
 
diff --git a/dhall_syntax/src/core/visitor.rs b/dhall_syntax/src/core/visitor.rs
index e39e95b..647f76f 100644
--- a/dhall_syntax/src/core/visitor.rs
+++ b/dhall_syntax/src/core/visitor.rs
@@ -278,21 +278,18 @@ where
     }
 }
 
-pub struct TraverseRefWithBindersVisitor<F1, F2, F4> {
+pub struct TraverseRefWithBindersVisitor<F1, F2> {
     pub visit_subexpr: F1,
     pub visit_under_binder: F2,
-    pub visit_embed: F4,
 }
 
-impl<'a, SE, E, SE2, E2, Err, F1, F2, F4>
-    ExprFFallibleVisitor<'a, SE, SE2, E, E2>
-    for TraverseRefWithBindersVisitor<F1, F2, F4>
+impl<'a, SE, E, SE2, Err, F1, F2> ExprFFallibleVisitor<'a, SE, SE2, E, E>
+    for TraverseRefWithBindersVisitor<F1, F2>
 where
     SE: 'a,
-    E: 'a,
+    E: 'a + Clone,
     F1: FnMut(&'a SE) -> Result<SE2, Err>,
     F2: FnOnce(&'a Label, &'a SE) -> Result<SE2, Err>,
-    F4: FnOnce(&'a E) -> Result<E2, Err>,
 {
     type Error = Err;
 
@@ -306,68 +303,45 @@ where
     ) -> Result<SE2, Self::Error> {
         (self.visit_under_binder)(label, subexpr)
     }
-    fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
-        (self.visit_embed)(embed)
+    fn visit_embed(self, embed: &'a E) -> Result<E, Self::Error> {
+        Ok(embed.clone())
     }
 }
 
-pub struct TraverseRefVisitor<F1, F3> {
+pub struct TraverseRefVisitor<F1> {
     pub visit_subexpr: F1,
-    pub visit_embed: F3,
 }
 
-impl<'a, SE, E, SE2, E2, Err, F1, F3> ExprFFallibleVisitor<'a, SE, SE2, E, E2>
-    for TraverseRefVisitor<F1, F3>
+impl<'a, SE, E, SE2, Err, F1> ExprFFallibleVisitor<'a, SE, SE2, E, E>
+    for TraverseRefVisitor<F1>
 where
     SE: 'a,
-    E: 'a,
+    E: 'a + Clone,
     F1: FnMut(&'a SE) -> Result<SE2, Err>,
-    F3: FnOnce(&'a E) -> Result<E2, Err>,
 {
     type Error = Err;
 
     fn visit_subexpr(&mut self, subexpr: &'a SE) -> Result<SE2, Self::Error> {
         (self.visit_subexpr)(subexpr)
     }
-    fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
-        (self.visit_embed)(embed)
-    }
-}
-
-pub struct TraverseEmbedVisitor<F1>(pub F1);
-
-impl<'a, 'b, E, E2, Err, F1>
-    ExprFFallibleVisitor<'a, SubExpr<E>, SubExpr<E2>, E, E2>
-    for &'b mut TraverseEmbedVisitor<F1>
-where
-    F1: FnMut(&E) -> Result<E2, Err>,
-{
-    type Error = Err;
-
-    fn visit_subexpr(
-        &mut self,
-        subexpr: &'a SubExpr<E>,
-    ) -> Result<SubExpr<E2>, Self::Error> {
-        Ok(subexpr.rewrap(subexpr.as_ref().visit(&mut **self)?))
-    }
-    fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
-        (self.0)(embed)
+    fn visit_embed(self, embed: &'a E) -> Result<E, Self::Error> {
+        Ok(embed.clone())
     }
 }
 
 pub struct ResolveVisitor<F1>(pub F1);
 
-impl<'a, 'b, E, E2, Err, F1>
-    ExprFFallibleVisitor<'a, SubExpr<E>, SubExpr<E2>, E, E2>
+impl<'a, 'b, E2, Err, F1>
+    ExprFFallibleVisitor<'a, SubExpr<Import>, SubExpr<E2>, Import, E2>
     for &'b mut ResolveVisitor<F1>
 where
-    F1: FnMut(&E) -> Result<E2, Err>,
+    F1: FnMut(&Import) -> Result<E2, Err>,
 {
     type Error = Err;
 
     fn visit_subexpr(
         &mut self,
-        subexpr: &'a SubExpr<E>,
+        subexpr: &'a SubExpr<Import>,
     ) -> Result<SubExpr<E2>, Self::Error> {
         Ok(subexpr.rewrap(
             subexpr
@@ -375,7 +349,7 @@ where
                 .traverse_resolve_with_visitor(&mut **self)?,
         ))
     }
-    fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
+    fn visit_embed(self, embed: &'a Import) -> Result<E2, Self::Error> {
         (self.0)(embed)
     }
 }
diff --git a/dhall_syntax/src/printer.rs b/dhall_syntax/src/printer.rs
index 25d4ca8..48e56be 100644
--- a/dhall_syntax/src/printer.rs
+++ b/dhall_syntax/src/printer.rs
@@ -156,7 +156,7 @@ impl<A: Display + Clone> Expr<A> {
         };
 
         // Annotate subexpressions with the appropriate phase, defaulting to Base
-        let phased_self = match self.map_ref_simple(|e| PhasedExpr(e, Base)) {
+        let phased_self = match self.map_ref(|e| PhasedExpr(e, Base)) {
             Pi(a, b, c) => {
                 if &String::from(&a) == "_" {
                     Pi(a, b.phase(Operator), c)
-- 
cgit v1.3.1


From 67cdda53d95057174b86878f22dbc0efc0255fd9 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Wed, 14 Aug 2019 22:55:00 +0200
Subject: Fix typo in normalization

---
 dhall/src/core/value.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 20a6021..845596b 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -107,7 +107,7 @@ impl Value {
                 ))
             };
             (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
-                rc(ExprF::Pi(
+                rc(ExprF::Lam(
                     stringify!($var).into(),
                     make_expr!($($ty)*),
                     make_expr!($($rest)*)
-- 
cgit v1.3.1


From ba19f41873fec98bb24ba709f4b76c3f58ca5aaa Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Thu, 15 Aug 2019 13:05:23 +0200
Subject: Fix bug in shifting contexts

---
 dhall/src/core/context.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index 62affcf..8d14415 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -97,7 +97,16 @@ impl<T> Context<T> {
     where
         T: Clone + Shift,
     {
-        Some(self.do_with_var(var, |var, i| Ok(i.shift(delta, &var)?))?)
+        if delta < 0 {
+            Some(self.do_with_var(var, |var, i| Ok(i.shift(delta, &var)?))?)
+        } else {
+            Some(Context(Rc::new(
+                self.0
+                    .iter()
+                    .map(|(l, i)| Ok((l.clone(), i.shift(delta, &var)?)))
+                    .collect::<Result<_, _>>()?,
+            )))
+        }
     }
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self
     where
-- 
cgit v1.3.1


From aabca76a62256aa7cad66c2016ed504e49651d5a Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Thu, 15 Aug 2019 13:06:56 +0200
Subject: Remove special closures from Value

Instead construct their values directly
---
 dhall/src/core/value.rs      | 95 +------------------------------------------
 dhall/src/core/var.rs        |  6 +++
 dhall/src/phase/normalize.rs | 97 +++++++++++++++++++++++++-------------------
 3 files changed, 62 insertions(+), 136 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 845596b..036a20c 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -30,13 +30,6 @@ pub enum Value {
     Pi(AlphaLabel, TypedThunk, TypedThunk),
     // Invariant: the evaluation must not be able to progress further.
     AppliedBuiltin(Builtin, Vec<Thunk>),
-    /// `λ(x: a) -> Some x`
-    OptionalSomeClosure(TypedThunk),
-    /// `λ(x : a) -> λ(xs : List a) -> [ x ] # xs`
-    /// `λ(xs : List a) -> [ x ] # xs`
-    ListConsClosure(TypedThunk, Option<Thunk>),
-    /// `λ(x : Natural) -> x + 1`
-    NaturalSuccClosure,
 
     Var(AlphaVar),
     Const(Const),
@@ -74,47 +67,6 @@ impl Value {
     /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
     /// if alpha is `true`
     pub fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
-        // Ad-hoc macro to help construct the unapplied closures
-        macro_rules! make_expr {
-            (Natural) => { rc(ExprF::Builtin(Builtin::Natural)) };
-            (var($var:ident)) => {
-                rc(ExprF::Var(dhall_syntax::V(stringify!($var).into(), 0)))
-            };
-            ($var:ident) => { $var };
-            (List $($rest:tt)*) => {
-                rc(ExprF::App(
-                    rc(ExprF::Builtin(Builtin::List)),
-                    make_expr!($($rest)*)
-                ))
-            };
-            (Some $($rest:tt)*) => {
-                rc(ExprF::SomeLit(
-                    make_expr!($($rest)*)
-                ))
-            };
-            (1 + $($rest:tt)*) => {
-                rc(ExprF::BinOp(
-                    dhall_syntax::BinOp::NaturalPlus,
-                    rc(ExprF::NaturalLit(1)),
-                    make_expr!($($rest)*)
-                ))
-            };
-            ([ $($head:tt)* ] # $($tail:tt)*) => {
-                rc(ExprF::BinOp(
-                    dhall_syntax::BinOp::ListAppend,
-                    rc(ExprF::NEListLit(vec![make_expr!($($head)*)])),
-                    make_expr!($($tail)*)
-                ))
-            };
-            (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
-                rc(ExprF::Lam(
-                    stringify!($var).into(),
-                    make_expr!($($ty)*),
-                    make_expr!($($rest)*)
-                ))
-            };
-        }
-
         match self {
             Value::Lam(x, t, e) => rc(ExprF::Lam(
                 x.to_label_maybe_alpha(alpha),
@@ -131,27 +83,6 @@ impl Value {
                 }
                 e
             }
-            Value::OptionalSomeClosure(n) => {
-                let a = n.normalize_to_expr_maybe_alpha(alpha);
-                make_expr!(λ(x: a) -> Some var(x))
-            }
-            Value::ListConsClosure(a, None) => {
-                // Avoid accidental capture of the new `x` variable
-                let a1 = a.under_binder(Label::from("x"));
-                let a1 = a1.normalize_to_expr_maybe_alpha(alpha);
-                let a = a.normalize_to_expr_maybe_alpha(alpha);
-                make_expr!(λ(x : a) -> λ(xs : List a1) -> [ var(x) ] # var(xs))
-            }
-            Value::ListConsClosure(n, Some(v)) => {
-                // Avoid accidental capture of the new `xs` variable
-                let v = v.under_binder(Label::from("xs"));
-                let v = v.normalize_to_expr_maybe_alpha(alpha);
-                let a = n.normalize_to_expr_maybe_alpha(alpha);
-                make_expr!(λ(xs : List a) -> [ v ] # var(xs))
-            }
-            Value::NaturalSuccClosure => {
-                make_expr!(λ(x : Natural) -> 1 + var(x))
-            }
             Value::Pi(x, t, e) => rc(ExprF::Pi(
                 x.to_label_maybe_alpha(alpha),
                 t.normalize_to_expr_maybe_alpha(alpha),
@@ -257,8 +188,7 @@ impl Value {
 
     pub fn normalize_mut(&mut self) {
         match self {
-            Value::NaturalSuccClosure
-            | Value::Var(_)
+            Value::Var(_)
             | Value::Const(_)
             | Value::BoolLit(_)
             | Value::NaturalLit(_)
@@ -266,7 +196,6 @@ impl Value {
             | Value::DoubleLit(_) => {}
 
             Value::EmptyOptionalLit(tth)
-            | Value::OptionalSomeClosure(tth)
             | Value::EmptyListLit(tth) => {
                 tth.normalize_mut();
             }
@@ -287,12 +216,6 @@ impl Value {
                     x.normalize_mut();
                 }
             }
-            Value::ListConsClosure(t, v) => {
-                t.normalize_mut();
-                for x in v.iter_mut() {
-                    x.normalize_mut();
-                }
-            }
             Value::NEListLit(elts) => {
                 for x in elts.iter_mut() {
                     x.normalize_mut();
@@ -375,14 +298,6 @@ impl Shift for Value {
                     .map(|v| Ok(v.shift(delta, var)?))
                     .collect::<Result<_, _>>()?,
             ),
-            Value::NaturalSuccClosure => Value::NaturalSuccClosure,
-            Value::OptionalSomeClosure(tth) => {
-                Value::OptionalSomeClosure(tth.shift(delta, var)?)
-            }
-            Value::ListConsClosure(t, v) => Value::ListConsClosure(
-                t.shift(delta, var)?,
-                v.as_ref().map(|v| Ok(v.shift(delta, var)?)).transpose()?,
-            ),
             Value::Pi(x, t, e) => Value::Pi(
                 x.clone(),
                 t.shift(delta, var)?,
@@ -516,14 +431,6 @@ impl Subst<Typed> for Value {
                 t.subst_shift(var, val),
                 e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
             ),
-            Value::NaturalSuccClosure => Value::NaturalSuccClosure,
-            Value::OptionalSomeClosure(tth) => {
-                Value::OptionalSomeClosure(tth.subst_shift(var, val))
-            }
-            Value::ListConsClosure(t, v) => Value::ListConsClosure(
-                t.subst_shift(var, val),
-                v.as_ref().map(|v| v.subst_shift(var, val)),
-            ),
             Value::Pi(x, t, e) => Value::Pi(
                 x.clone(),
                 t.subst_shift(var, val),
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index 35bff80..0faa091 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -67,6 +67,12 @@ impl AlphaVar {
             alpha: None,
         }
     }
+    pub fn from_var_and_alpha(normal: V<Label>, alpha: usize) -> Self {
+        AlphaVar {
+            normal,
+            alpha: Some(V((), alpha)),
+        }
+    }
 }
 
 impl AlphaLabel {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index adbcb02..f11269e 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -1,19 +1,61 @@
 use std::collections::HashMap;
 
 use dhall_syntax::{
-    BinOp, Builtin, ExprF, InterpolatedText, InterpolatedTextContents,
+    BinOp, Builtin, ExprF, InterpolatedText, InterpolatedTextContents, Label,
     NaiveDouble,
 };
 
 use crate::core::context::NormalizationContext;
 use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
-use crate::core::var::Subst;
+use crate::core::var::{Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr, ResolvedSubExpr, Typed};
 
 pub type InputSubExpr = ResolvedSubExpr;
 pub type OutputSubExpr = NormalizedSubExpr;
 
+// Ad-hoc macro to help construct closures
+macro_rules! make_closure {
+    (#$var:ident) => { $var.clone() };
+    (var($var:ident, $n:expr)) => {{
+        let var = crate::core::var::AlphaVar::from_var_and_alpha(
+            Label::from(stringify!($var)).into(),
+            $n
+        );
+        Value::Var(var).into_thunk()
+    }};
+    (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
+        Value::Lam(
+            Label::from(stringify!($var)).into(),
+            TypedThunk::from_thunk_untyped(make_closure!($($ty)*)),
+            make_closure!($($rest)*),
+        ).into_thunk()
+    };
+    (Natural) => { Value::from_builtin(Builtin::Natural).into_thunk() };
+    (List $($rest:tt)*) => {
+        Value::from_builtin(Builtin::List)
+            .app_thunk(make_closure!($($rest)*))
+            .into_thunk()
+    };
+    (Some $($rest:tt)*) => {
+        Value::NEOptionalLit(make_closure!($($rest)*)).into_thunk()
+    };
+    (1 + $($rest:tt)*) => {
+        Value::PartialExpr(ExprF::BinOp(
+            dhall_syntax::BinOp::NaturalPlus,
+            make_closure!($($rest)*),
+            Thunk::from_value(Value::NaturalLit(1)),
+        )).into_thunk()
+    };
+    ([ $($head:tt)* ] # $($tail:tt)*) => {
+        Value::PartialExpr(ExprF::BinOp(
+            dhall_syntax::BinOp::ListAppend,
+            Value::NEListLit(vec![make_closure!($($head)*)]).into_thunk(),
+            make_closure!($($tail)*),
+        )).into_thunk()
+    };
+}
+
 #[allow(clippy::cognitive_complexity)]
 pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
     use dhall_syntax::Builtin::*;
@@ -179,10 +221,15 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             _ => Ok((
                 r,
                 f.app_val(Value::from_builtin(List).app_thunk(t.clone()))
-                    .app_val(ListConsClosure(
-                        TypedThunk::from_thunk(t.clone()),
-                        None,
-                    ))
+                    .app_thunk({
+                        // Move `t` under new `x` variable
+                        let t1 = t.under_binder(Label::from("x"));
+                        make_closure!(
+                            λ(x : #t) ->
+                            λ(xs : List #t1) ->
+                            [ var(x, 1) ] # var(xs, 0)
+                        )
+                    })
                     .app_val(EmptyListLit(TypedThunk::from_thunk(t.clone()))),
             )),
         },
@@ -214,9 +261,7 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             _ => Ok((
                 r,
                 f.app_val(Value::from_builtin(Optional).app_thunk(t.clone()))
-                    .app_val(OptionalSomeClosure(TypedThunk::from_thunk(
-                        t.clone(),
-                    )))
+                    .app_thunk(make_closure!(λ(x: #t) -> Some var(x, 0)))
                     .app_val(EmptyOptionalLit(TypedThunk::from_thunk(
                         t.clone(),
                     ))),
@@ -240,7 +285,7 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             _ => Ok((
                 r,
                 f.app_val(Value::from_builtin(Natural))
-                    .app_val(NaturalSuccClosure)
+                    .app_thunk(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
                     .app_val(NaturalLit(0)),
             )),
         },
@@ -284,38 +329,6 @@ pub fn apply_any(f: Thunk, a: Thunk) -> Value {
             let args = args.iter().cloned().chain(once(a.clone())).collect();
             apply_builtin(*b, args)
         }
-        Value::OptionalSomeClosure(_) => Value::NEOptionalLit(a),
-        Value::ListConsClosure(t, None) => {
-            Value::ListConsClosure(t.clone(), Some(a))
-        }
-        Value::ListConsClosure(_, Some(x)) => {
-            let a_borrow = a.as_value();
-            match &*a_borrow {
-                Value::EmptyListLit(_) => Value::NEListLit(vec![x.clone()]),
-                Value::NEListLit(xs) => {
-                    use std::iter::once;
-                    let xs =
-                        once(x.clone()).chain(xs.iter().cloned()).collect();
-                    Value::NEListLit(xs)
-                }
-                _ => {
-                    drop(f_borrow);
-                    drop(a_borrow);
-                    fallback(f, a)
-                }
-            }
-        }
-        Value::NaturalSuccClosure => {
-            let a_borrow = a.as_value();
-            match &*a_borrow {
-                Value::NaturalLit(n) => Value::NaturalLit(n + 1),
-                _ => {
-                    drop(f_borrow);
-                    drop(a_borrow);
-                    fallback(f, a)
-                }
-            }
-        }
         Value::UnionConstructor(l, kts) => {
             Value::UnionLit(l.clone(), a, kts.clone())
         }
-- 
cgit v1.3.1


From a9804009f405be7e8a89e301f280ee9d51b57e5e Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Thu, 15 Aug 2019 13:08:25 +0200
Subject: Custom Debug impls to improve debug legibility

---
 dhall/src/core/thunk.rs | 21 ++++++++++++++++++++-
 dhall/src/core/var.rs   | 19 +++++++++++++++++--
 2 files changed, 37 insertions(+), 3 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 7c5c537..14d8792 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -39,7 +39,7 @@ enum ThunkInternal {
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
 /// sharing computation automatically.
 /// Uses a RefCell to share computation.
-#[derive(Debug, Clone)]
+#[derive(Clone)]
 pub struct Thunk(Rc<RefCell<ThunkInternal>>);
 
 /// A thunk in type position. Can optionally store a Type from the typechecking phase to preserve
@@ -393,3 +393,22 @@ impl std::cmp::PartialEq for TypedThunk {
     }
 }
 impl std::cmp::Eq for TypedThunk {}
+
+impl std::fmt::Debug for Thunk {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let b: &ThunkInternal = &self.0.borrow();
+        match b {
+            ThunkInternal::Value(m, v) => {
+                f.debug_tuple(&format!("Thunk@{:?}", m)).field(v).finish()
+            }
+            ThunkInternal::PartialExpr(e) => {
+                f.debug_tuple("Thunk@PartialExpr").field(e).finish()
+            }
+            ThunkInternal::Unnormalized(ctx, e) => f
+                .debug_tuple("Thunk@Unnormalized")
+                .field(ctx)
+                .field(e)
+                .finish(),
+        }
+    }
+}
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index 0faa091..d53c194 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{Label, V};
 /// Stores a pair of variables: a normal one and if relevant one
 /// that corresponds to the alpha-normalized version of the first one.
 /// Equality is up to alpha-equivalence.
-#[derive(Debug, Clone, Eq)]
+#[derive(Clone, Eq)]
 pub struct AlphaVar {
     normal: V<Label>,
     alpha: Option<V<()>>,
@@ -13,7 +13,7 @@ pub struct AlphaVar {
 
 // Exactly like a Label, but equality returns always true.
 // This is so that Value equality is exactly alpha-equivalence.
-#[derive(Debug, Clone, Eq)]
+#[derive(Clone, Eq)]
 pub struct AlphaLabel(Label);
 
 pub trait Shift: Sized {
@@ -125,6 +125,21 @@ impl std::cmp::PartialEq for AlphaLabel {
     }
 }
 
+impl std::fmt::Debug for AlphaVar {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match &self.alpha {
+            Some(a) => write!(f, "AlphaVar({}, {})", self.normal, a.1),
+            None => write!(f, "AlphaVar({}, free)", self.normal),
+        }
+    }
+}
+
+impl std::fmt::Debug for AlphaLabel {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "AlphaLabel({})", &self.0)
+    }
+}
+
 impl From<Label> for AlphaVar {
     fn from(x: Label) -> AlphaVar {
         AlphaVar {
-- 
cgit v1.3.1


From 9e38d92bf481da8e34081c81c813acd802efa016 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Thu, 15 Aug 2019 22:03:41 +0200
Subject: Fix variable substitution

I have no idea how this didn't get caught before
---
 dhall/src/core/value.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 036a20c..75ef5a5 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -436,10 +436,8 @@ impl Subst<Typed> for Value {
                 t.subst_shift(var, val),
                 e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
             ),
-            Value::Var(v) => match v.shift(-1, var) {
-                None => val.to_value().clone(),
-                Some(newvar) => Value::Var(newvar),
-            },
+            Value::Var(v) if v == var => val.to_value(),
+            Value::Var(v) => Value::Var(v.shift(-1, var).unwrap()),
             Value::Const(c) => Value::Const(*c),
             Value::BoolLit(b) => Value::BoolLit(*b),
             Value::NaturalLit(n) => Value::NaturalLit(*n),
-- 
cgit v1.3.1


From 91ba644fa47c29feb57dba957ee8aa115ed95fef Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Thu, 15 Aug 2019 22:12:25 +0200
Subject: rustfmt

---
 dhall/src/core/value.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 75ef5a5..19be56a 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -195,8 +195,7 @@ impl Value {
             | Value::IntegerLit(_)
             | Value::DoubleLit(_) => {}
 
-            Value::EmptyOptionalLit(tth)
-            | Value::EmptyListLit(tth) => {
+            Value::EmptyOptionalLit(tth) | Value::EmptyListLit(tth) => {
                 tth.normalize_mut();
             }
 
-- 
cgit v1.3.1


From 88ebc0f9d561a2541aad84a3152511a0439db8b4 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 17:56:19 +0200
Subject: Reduce api surface of dhall crate

Helps detect unused code
---
 dhall/src/core/context.rs    |  8 +++----
 dhall/src/core/thunk.rs      | 56 ++++++++++++++++++++++----------------------
 dhall/src/core/value.rs      | 19 +++++----------
 dhall/src/core/var.rs        | 14 +++++------
 dhall/src/phase/binary.rs    |  4 ++--
 dhall/src/phase/mod.rs       | 41 ++++++++++++++------------------
 dhall/src/phase/normalize.rs | 14 +++++------
 dhall/src/phase/parse.rs     |  8 +++----
 dhall/src/phase/resolve.rs   |  8 +++----
 dhall/src/phase/typecheck.rs | 12 +++++-----
 serde_dhall/src/lib.rs       | 14 +++++------
 11 files changed, 92 insertions(+), 106 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index 8d14415..9230a2e 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -10,19 +10,19 @@ use crate::error::TypeError;
 use crate::phase::{Type, Typed};
 
 #[derive(Debug, Clone)]
-pub enum CtxItem<T> {
+enum CtxItem<T> {
     Kept(AlphaVar, T),
     Replaced(Thunk, T),
 }
 
 #[derive(Debug, Clone)]
-pub struct Context<T>(Rc<Vec<(Label, CtxItem<T>)>>);
+struct Context<T>(Rc<Vec<(Label, CtxItem<T>)>>);
 
 #[derive(Debug, Clone)]
-pub struct NormalizationContext(Context<()>);
+pub(crate) struct NormalizationContext(Context<()>);
 
 #[derive(Debug, Clone)]
-pub struct TypecheckContext(Context<Type>);
+pub(crate) struct TypecheckContext(Context<Type>);
 
 impl<T> Context<T> {
     pub fn new() -> Self {
diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 14d8792..54a5442 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -115,21 +115,21 @@ impl ThunkInternal {
 }
 
 impl Thunk {
-    pub fn new(ctx: NormalizationContext, e: InputSubExpr) -> Thunk {
+    pub(crate) fn new(ctx: NormalizationContext, e: InputSubExpr) -> Thunk {
         ThunkInternal::Unnormalized(ctx, e).into_thunk()
     }
 
-    pub fn from_value(v: Value) -> Thunk {
+    pub(crate) fn from_value(v: Value) -> Thunk {
         ThunkInternal::Value(WHNF, v).into_thunk()
     }
 
-    pub fn from_partial_expr(e: ExprF<Thunk, Normalized>) -> Thunk {
+    pub(crate) fn from_partial_expr(e: ExprF<Thunk, Normalized>) -> Thunk {
         ThunkInternal::PartialExpr(e).into_thunk()
     }
 
     // Normalizes contents to normal form; faster than `normalize_nf` if
     // no one else shares this thunk
-    pub fn normalize_mut(&mut self) {
+    pub(crate) fn normalize_mut(&mut self) {
         match Rc::get_mut(&mut self.0) {
             // Mutate directly if sole owner
             Some(refcell) => RefCell::get_mut(refcell).normalize_nf(),
@@ -167,37 +167,37 @@ impl Thunk {
 
     // WARNING: avoid normalizing any thunk while holding on to this ref
     // or you could run into BorrowMut panics
-    pub fn normalize_nf(&self) -> Ref<Value> {
+    pub(crate) fn normalize_nf(&self) -> Ref<Value> {
         self.do_normalize_nf();
         Ref::map(self.0.borrow(), ThunkInternal::as_nf)
     }
 
     // WARNING: avoid normalizing any thunk while holding on to this ref
     // or you could run into BorrowMut panics
-    pub fn as_value(&self) -> Ref<Value> {
+    pub(crate) fn as_value(&self) -> Ref<Value> {
         self.do_normalize_whnf();
         Ref::map(self.0.borrow(), ThunkInternal::as_whnf)
     }
 
-    pub fn to_value(&self) -> Value {
+    pub(crate) fn to_value(&self) -> Value {
         self.as_value().clone()
     }
 
-    pub fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
         self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub fn app_val(&self, val: Value) -> Value {
+    pub(crate) fn app_val(&self, val: Value) -> Value {
         self.app_thunk(val.into_thunk())
     }
 
-    pub fn app_thunk(&self, th: Thunk) -> Value {
+    pub(crate) fn app_thunk(&self, th: Thunk) -> Value {
         apply_any(self.clone(), th)
     }
 }
 
 impl TypedThunk {
-    pub fn from_value(v: Value) -> TypedThunk {
+    pub(crate) fn from_value(v: Value) -> TypedThunk {
         TypedThunk::from_thunk(Thunk::from_value(v))
     }
 
@@ -205,11 +205,11 @@ impl TypedThunk {
         TypedThunk::from_thunk_untyped(th)
     }
 
-    pub fn from_type(t: Type) -> TypedThunk {
+    pub(crate) fn from_type(t: Type) -> TypedThunk {
         t.into_typethunk()
     }
 
-    pub fn normalize_nf(&self) -> Value {
+    pub(crate) fn normalize_nf(&self) -> Value {
         match self {
             TypedThunk::Const(c) => Value::Const(*c),
             TypedThunk::Untyped(thunk) | TypedThunk::Typed(thunk, _) => {
@@ -218,53 +218,53 @@ impl TypedThunk {
         }
     }
 
-    pub fn to_typed(&self) -> Typed {
+    pub(crate) fn to_typed(&self) -> Typed {
         self.clone().into_typed()
     }
 
-    pub fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
         self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
+    pub(crate) fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
         TypedThunk::Typed(th, Box::new(t))
     }
-    pub fn from_thunk_untyped(th: Thunk) -> Self {
+    pub(crate) fn from_thunk_untyped(th: Thunk) -> Self {
         TypedThunk::Untyped(th)
     }
-    pub fn from_const(c: Const) -> Self {
+    pub(crate) fn from_const(c: Const) -> Self {
         TypedThunk::Const(c)
     }
-    pub fn from_value_untyped(v: Value) -> Self {
+    pub(crate) fn from_value_untyped(v: Value) -> Self {
         TypedThunk::from_thunk_untyped(Thunk::from_value(v))
     }
 
     // TODO: Avoid cloning if possible
-    pub fn to_value(&self) -> Value {
+    pub(crate) fn to_value(&self) -> Value {
         match self {
             TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.to_value(),
             TypedThunk::Const(c) => Value::Const(*c),
         }
     }
-    pub fn to_expr(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
         self.to_value().normalize_to_expr()
     }
-    pub fn to_expr_alpha(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.to_value().normalize_to_expr_maybe_alpha(true)
     }
-    pub fn to_thunk(&self) -> Thunk {
+    pub(crate) fn to_thunk(&self) -> Thunk {
         match self {
             TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.clone(),
             TypedThunk::Const(c) => Thunk::from_value(Value::Const(*c)),
         }
     }
-    pub fn to_type(&self) -> Type {
+    pub(crate) fn to_type(&self) -> Type {
         self.clone().into_typed().into_type()
     }
-    pub fn into_typed(self) -> Typed {
+    pub(crate) fn into_typed(self) -> Typed {
         Typed::from_typethunk(self)
     }
-    pub fn as_const(&self) -> Option<Const> {
+    pub(crate) fn as_const(&self) -> Option<Const> {
         // TODO: avoid clone
         match &self.to_value() {
             Value::Const(c) => Some(*c),
@@ -272,7 +272,7 @@ impl TypedThunk {
         }
     }
 
-    pub fn normalize_mut(&mut self) {
+    pub(crate) fn normalize_mut(&mut self) {
         match self {
             TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => {
                 th.normalize_mut()
@@ -281,7 +281,7 @@ impl TypedThunk {
         }
     }
 
-    pub fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
         match self {
             TypedThunk::Untyped(_) => Err(TypeError::new(
                 &TypecheckContext::new(),
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 19be56a..61a8eea 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -56,17 +56,17 @@ pub enum Value {
 }
 
 impl Value {
-    pub fn into_thunk(self) -> Thunk {
+    pub(crate) fn into_thunk(self) -> Thunk {
         Thunk::from_value(self)
     }
 
     /// Convert the value to a fully normalized syntactic expression
-    pub fn normalize_to_expr(&self) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr(&self) -> OutputSubExpr {
         self.normalize_to_expr_maybe_alpha(false)
     }
     /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
     /// if alpha is `true`
-    pub fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
         match self {
             Value::Lam(x, t, e) => rc(ExprF::Lam(
                 x.to_label_maybe_alpha(alpha),
@@ -179,14 +179,7 @@ impl Value {
         }
     }
 
-    // Deprecated
-    pub fn normalize(&self) -> Value {
-        let mut v = self.clone();
-        v.normalize_mut();
-        v
-    }
-
-    pub fn normalize_mut(&mut self) {
+    pub(crate) fn normalize_mut(&mut self) {
         match self {
             Value::Var(_)
             | Value::Const(_)
@@ -264,12 +257,12 @@ impl Value {
     }
 
     /// Apply to a value
-    pub fn app(self, val: Value) -> Value {
+    pub(crate) fn app(self, val: Value) -> Value {
         self.app_val(val)
     }
 
     /// Apply to a value
-    pub fn app_val(self, val: Value) -> Value {
+    pub(crate) fn app_val(self, val: Value) -> Value {
         self.app_thunk(val.into_thunk())
     }
 
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index d53c194..4ef1b93 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -16,7 +16,7 @@ pub struct AlphaVar {
 #[derive(Clone, Eq)]
 pub struct AlphaLabel(Label);
 
-pub trait Shift: Sized {
+pub(crate) trait Shift: Sized {
     // Shift an expression to move it around binders without changing the meaning of its free
     // variables. Shift by 1 to move an expression under a binder. Shift by -1 to extract an
     // expression from under a binder, if the expression does not refer to that bound variable.
@@ -50,24 +50,24 @@ pub trait Shift: Sized {
     }
 }
 
-pub trait Subst<T> {
+pub(crate) trait Subst<T> {
     fn subst_shift(&self, var: &AlphaVar, val: &T) -> Self;
 }
 
 impl AlphaVar {
-    pub fn to_var(&self, alpha: bool) -> V<Label> {
+    pub(crate) fn to_var(&self, alpha: bool) -> V<Label> {
         match (alpha, &self.alpha) {
             (true, Some(x)) => V("_".into(), x.1),
             _ => self.normal.clone(),
         }
     }
-    pub fn from_var(normal: V<Label>) -> Self {
+    pub(crate) fn from_var(normal: V<Label>) -> Self {
         AlphaVar {
             normal,
             alpha: None,
         }
     }
-    pub fn from_var_and_alpha(normal: V<Label>, alpha: usize) -> Self {
+    pub(crate) fn from_var_and_alpha(normal: V<Label>, alpha: usize) -> Self {
         AlphaVar {
             normal,
             alpha: Some(V((), alpha)),
@@ -76,14 +76,14 @@ impl AlphaVar {
 }
 
 impl AlphaLabel {
-    pub fn to_label_maybe_alpha(&self, alpha: bool) -> Label {
+    pub(crate) fn to_label_maybe_alpha(&self, alpha: bool) -> Label {
         if alpha {
             "_".into()
         } else {
             self.to_label()
         }
     }
-    pub fn to_label(&self) -> Label {
+    pub(crate) fn to_label(&self) -> Label {
         self.clone().into()
     }
 }
diff --git a/dhall/src/phase/binary.rs b/dhall/src/phase/binary.rs
index 36dd471..3746635 100644
--- a/dhall/src/phase/binary.rs
+++ b/dhall/src/phase/binary.rs
@@ -11,14 +11,14 @@ use dhall_syntax::{
 use crate::error::{DecodeError, EncodeError};
 use crate::phase::DecodedSubExpr;
 
-pub fn decode(data: &[u8]) -> Result<DecodedSubExpr, DecodeError> {
+pub(crate) fn decode(data: &[u8]) -> Result<DecodedSubExpr, DecodeError> {
     match serde_cbor::de::from_slice(data) {
         Ok(v) => cbor_value_to_dhall(&v),
         Err(e) => Err(DecodeError::CBORError(e)),
     }
 }
 
-pub fn encode<E>(expr: &SubExpr<E>) -> Result<Vec<u8>, EncodeError> {
+pub(crate) fn encode<E>(expr: &SubExpr<E>) -> Result<Vec<u8>, EncodeError> {
     serde_cbor::ser::to_vec(&Serialize::Expr(expr))
         .map_err(|e| EncodeError::CBORError(e))
 }
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 2700e99..778f990 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -50,11 +50,9 @@ impl Parsed {
     pub fn parse_str(s: &str) -> Result<Parsed, Error> {
         parse::parse_str(s)
     }
-    #[allow(dead_code)]
     pub fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
         parse::parse_binary_file(f)
     }
-    #[allow(dead_code)]
     pub fn parse_binary(data: &[u8]) -> Result<Parsed, Error> {
         parse::parse_binary(data)
     }
@@ -62,12 +60,10 @@ impl Parsed {
     pub fn resolve(self) -> Result<Resolved, ImportError> {
         resolve::resolve(self)
     }
-    #[allow(dead_code)]
     pub fn skip_resolve(self) -> Result<Resolved, ImportError> {
         resolve::skip_resolve_expr(self)
     }
 
-    #[allow(dead_code)]
     pub fn encode(&self) -> Result<Vec<u8>, EncodeError> {
         crate::phase::binary::encode(&self.0)
     }
@@ -82,7 +78,7 @@ impl Resolved {
     }
     /// Pretends this expression has been typechecked. Use with care.
     #[allow(dead_code)]
-    pub fn skip_typecheck(self) -> Typed {
+    pub(crate) fn skip_typecheck(self) -> Typed {
         typecheck::skip_typecheck(self)
     }
 }
@@ -101,29 +97,29 @@ impl Typed {
         Normalized(self)
     }
 
-    pub fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
+    pub(crate) fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
         Typed(TypedThunk::from_thunk_and_type(th, t))
     }
-    pub fn from_thunk_untyped(th: Thunk) -> Self {
+    pub(crate) fn from_thunk_untyped(th: Thunk) -> Self {
         Typed(TypedThunk::from_thunk_untyped(th))
     }
-    pub fn from_const(c: Const) -> Self {
+    pub(crate) fn from_const(c: Const) -> Self {
         Typed(TypedThunk::from_const(c))
     }
     pub fn from_value_untyped(v: Value) -> Self {
         Typed(TypedThunk::from_value_untyped(v))
     }
-    pub fn from_typethunk(th: TypedThunk) -> Self {
+    pub(crate) fn from_typethunk(th: TypedThunk) -> Self {
         Typed(th)
     }
 
-    pub fn to_value(&self) -> Value {
+    pub(crate) fn to_value(&self) -> Value {
         self.0.to_value()
     }
     pub fn to_expr(&self) -> NormalizedSubExpr {
         self.0.to_expr()
     }
-    pub fn to_expr_alpha(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.0.to_expr_alpha()
     }
     pub fn to_thunk(&self) -> Thunk {
@@ -134,24 +130,24 @@ impl Typed {
         self.clone()
     }
     // Deprecated
-    pub fn into_type(self) -> Type {
+    pub(crate) fn into_type(self) -> Type {
         self
     }
-    pub fn into_typethunk(self) -> TypedThunk {
+    pub(crate) fn into_typethunk(self) -> TypedThunk {
         self.0
     }
-    pub fn to_normalized(&self) -> Normalized {
+    pub(crate) fn to_normalized(&self) -> Normalized {
         self.clone().normalize()
     }
-    pub fn as_const(&self) -> Option<Const> {
+    pub(crate) fn as_const(&self) -> Option<Const> {
         self.0.as_const()
     }
 
-    pub fn normalize_mut(&mut self) {
+    pub(crate) fn normalize_mut(&mut self) {
         self.0.normalize_mut()
     }
 
-    pub fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
         self.0.get_type()
     }
 }
@@ -161,22 +157,21 @@ impl Normalized {
         crate::phase::binary::encode(&self.to_expr())
     }
 
-    #[allow(dead_code)]
-    pub fn to_expr(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
         self.0.to_expr()
     }
     #[allow(dead_code)]
-    pub fn to_expr_alpha(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.0.to_expr_alpha()
     }
     #[allow(dead_code)]
-    pub fn to_type(&self) -> Type {
+    pub(crate) fn to_type(&self) -> Type {
         self.0.to_type()
     }
-    pub fn to_value(&self) -> Value {
+    pub(crate) fn to_value(&self) -> Value {
         self.0.to_value()
     }
-    pub fn into_typed(self) -> Typed {
+    pub(crate) fn into_typed(self) -> Typed {
         self.0
     }
 }
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 02406f2..fd0197d 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -11,8 +11,8 @@ use crate::core::value::Value;
 use crate::core::var::{Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr, ResolvedSubExpr, Typed};
 
-pub type InputSubExpr = ResolvedSubExpr;
-pub type OutputSubExpr = NormalizedSubExpr;
+pub(crate) type InputSubExpr = ResolvedSubExpr;
+pub(crate) type OutputSubExpr = NormalizedSubExpr;
 
 // Ad-hoc macro to help construct closures
 macro_rules! make_closure {
@@ -57,7 +57,7 @@ macro_rules! make_closure {
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
+pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
     use dhall_syntax::Builtin::*;
     use Value::*;
 
@@ -315,7 +315,7 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
     }
 }
 
-pub fn apply_any(f: Thunk, a: Thunk) -> Value {
+pub(crate) fn apply_any(f: Thunk, a: Thunk) -> Value {
     let fallback = |f: Thunk, a: Thunk| Value::PartialExpr(ExprF::App(f, a));
 
     let f_borrow = f.as_value();
@@ -339,7 +339,7 @@ pub fn apply_any(f: Thunk, a: Thunk) -> Value {
     }
 }
 
-pub fn squash_textlit(
+pub(crate) fn squash_textlit(
     elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>,
 ) -> Vec<InterpolatedTextContents<Thunk>> {
     use std::mem::replace;
@@ -382,7 +382,7 @@ pub fn squash_textlit(
 }
 
 /// Reduces the imput expression to a Value. Evaluates as little as possible.
-pub fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
+pub(crate) fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
     match expr.as_ref() {
         ExprF::Embed(e) => return e.to_value(),
         ExprF::Var(v) => return ctx.lookup(v),
@@ -649,7 +649,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
     })
 }
 
-pub fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
+pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
     use Value::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, Lam,
         NEListLit, NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType,
diff --git a/dhall/src/phase/parse.rs b/dhall/src/phase/parse.rs
index 9f3f2f4..540ceea 100644
--- a/dhall/src/phase/parse.rs
+++ b/dhall/src/phase/parse.rs
@@ -8,7 +8,7 @@ use crate::error::Error;
 use crate::phase::resolve::ImportRoot;
 use crate::phase::Parsed;
 
-pub fn parse_file(f: &Path) -> Result<Parsed, Error> {
+pub(crate) fn parse_file(f: &Path) -> Result<Parsed, Error> {
     let mut buffer = String::new();
     File::open(f)?.read_to_string(&mut buffer)?;
     let expr = parse_expr(&*buffer)?;
@@ -16,19 +16,19 @@ pub fn parse_file(f: &Path) -> Result<Parsed, Error> {
     Ok(Parsed(expr, root))
 }
 
-pub fn parse_str(s: &str) -> Result<Parsed, Error> {
+pub(crate) fn parse_str(s: &str) -> Result<Parsed, Error> {
     let expr = parse_expr(s)?;
     let root = ImportRoot::LocalDir(std::env::current_dir()?);
     Ok(Parsed(expr, root))
 }
 
-pub fn parse_binary(data: &[u8]) -> Result<Parsed, Error> {
+pub(crate) fn parse_binary(data: &[u8]) -> Result<Parsed, Error> {
     let expr = crate::phase::binary::decode(data)?;
     let root = ImportRoot::LocalDir(std::env::current_dir()?);
     Ok(Parsed(expr, root))
 }
 
-pub fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
+pub(crate) fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
     let mut buffer = Vec::new();
     File::open(f)?.read_to_end(&mut buffer)?;
     let expr = crate::phase::binary::decode(&buffer)?;
diff --git a/dhall/src/phase/resolve.rs b/dhall/src/phase/resolve.rs
index dabecf2..27ae7a3 100644
--- a/dhall/src/phase/resolve.rs
+++ b/dhall/src/phase/resolve.rs
@@ -8,13 +8,13 @@ type Import = dhall_syntax::Import<NormalizedSubExpr>;
 
 /// A root from which to resolve relative imports.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub enum ImportRoot {
+pub(crate) enum ImportRoot {
     LocalDir(PathBuf),
 }
 
 type ImportCache = HashMap<Import, Normalized>;
 
-pub type ImportStack = Vec<Import>;
+pub(crate) type ImportStack = Vec<Import>;
 
 fn resolve_import(
     import: &Import,
@@ -90,11 +90,11 @@ fn do_resolve_expr(
     Ok(Resolved(expr))
 }
 
-pub fn resolve(e: Parsed) -> Result<Resolved, ImportError> {
+pub(crate) fn resolve(e: Parsed) -> Result<Resolved, ImportError> {
     do_resolve_expr(e, &mut HashMap::new(), &Vec::new())
 }
 
-pub fn skip_resolve_expr(
+pub(crate) fn skip_resolve_expr(
     Parsed(expr, _root): Parsed,
 ) -> Result<Resolved, ImportError> {
     let resolve = |import: &Import| -> Result<Normalized, ImportError> {
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 5eab8da..56fb5ed 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -147,7 +147,7 @@ fn function_check(a: Const, b: Const) -> Const {
     }
 }
 
-pub fn type_of_const(c: Const) -> Result<Type, TypeError> {
+pub(crate) fn type_of_const(c: Const) -> Result<Type, TypeError> {
     match c {
         Const::Type => Ok(Type::from_const(Const::Kind)),
         Const::Kind => Ok(Type::from_const(Const::Sort)),
@@ -300,14 +300,14 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
 
 /// Takes an expression that is meant to contain a Type
 /// and turn it into a type, typechecking it along the way.
-pub fn mktype(
+pub(crate) fn mktype(
     ctx: &TypecheckContext,
     e: SubExpr<Normalized>,
 ) -> Result<Type, TypeError> {
     Ok(type_with(ctx, e)?.to_type())
 }
 
-pub fn builtin_to_type(b: Builtin) -> Result<Type, TypeError> {
+pub(crate) fn builtin_to_type(b: Builtin) -> Result<Type, TypeError> {
     mktype(&TypecheckContext::new(), SubExpr::from_builtin(b))
 }
 
@@ -1009,15 +1009,15 @@ fn type_of(e: SubExpr<Normalized>) -> Result<Typed, TypeError> {
     Ok(e)
 }
 
-pub fn typecheck(e: Resolved) -> Result<Typed, TypeError> {
+pub(crate) fn typecheck(e: Resolved) -> Result<Typed, TypeError> {
     type_of(e.0)
 }
 
-pub fn typecheck_with(e: Resolved, ty: &Type) -> Result<Typed, TypeError> {
+pub(crate) fn typecheck_with(e: Resolved, ty: &Type) -> Result<Typed, TypeError> {
     let expr: SubExpr<_> = e.0;
     let ty: SubExpr<_> = ty.to_expr();
     type_of(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
 }
-pub fn skip_typecheck(e: Resolved) -> Typed {
+pub(crate) fn skip_typecheck(e: Resolved) -> Typed {
     Typed::from_thunk_untyped(Thunk::new(NormalizationContext::new(), e.0))
 }
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 14d8b47..71674a9 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -167,16 +167,14 @@ pub mod value {
             Self::from_dhall_value(DhallValue::from_builtin(b))
         }
         pub(crate) fn make_optional_type(t: Value) -> Self {
-            Self::from_dhall_value(DhallValue::AppliedBuiltin(
-                Builtin::Optional,
-                vec![t.to_thunk()],
-            ))
+            Self::from_dhall_value(
+                DhallValue::from_builtin(Builtin::Optional).app_thunk(t.to_thunk()),
+            )
         }
         pub(crate) fn make_list_type(t: Value) -> Self {
-            Self::from_dhall_value(DhallValue::AppliedBuiltin(
-                Builtin::List,
-                vec![t.to_thunk()],
-            ))
+            Self::from_dhall_value(
+                DhallValue::from_builtin(Builtin::List).app_thunk(t.to_thunk()),
+            )
         }
         // Made public for the StaticType derive macro
         #[doc(hidden)]
-- 
cgit v1.3.1


From 5f0d69671b44ba1dff6becb9ebc7f6e74241e3e2 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 18:14:55 +0200
Subject: Remove dead code

---
 dhall/src/core/context.rs    | 31 -----------------------
 dhall/src/core/thunk.rs      | 59 +++++++++++++-------------------------------
 dhall/src/core/value.rs      |  5 +++-
 dhall/src/core/var.rs        |  6 -----
 dhall/src/phase/mod.rs       |  8 ------
 dhall/src/phase/normalize.rs | 22 +----------------
 dhall/src/phase/typecheck.rs | 10 ++++----
 serde_dhall/src/lib.rs       |  3 ++-
 8 files changed, 29 insertions(+), 115 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index 9230a2e..3c07c1c 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -18,9 +18,6 @@ enum CtxItem<T> {
 #[derive(Debug, Clone)]
 struct Context<T>(Rc<Vec<(Label, CtxItem<T>)>>);
 
-#[derive(Debug, Clone)]
-pub(crate) struct NormalizationContext(Context<()>);
-
 #[derive(Debug, Clone)]
 pub(crate) struct TypecheckContext(Context<Type>);
 
@@ -117,22 +114,6 @@ impl<T> Context<T> {
     }
 }
 
-impl NormalizationContext {
-    pub fn new() -> Self {
-        NormalizationContext(Context::new())
-    }
-    pub fn skip(&self, x: &Label) -> Self {
-        NormalizationContext(self.0.insert_kept(x, ()))
-    }
-    pub fn lookup(&self, var: &V<Label>) -> Value {
-        match self.0.lookup(var) {
-            Ok(CtxItem::Replaced(t, ())) => t.to_value(),
-            Ok(CtxItem::Kept(newvar, ())) => Value::Var(newvar.clone()),
-            Err(var) => Value::Var(AlphaVar::from_var(var)),
-        }
-    }
-}
-
 impl TypecheckContext {
     pub fn new() -> Self {
         TypecheckContext(Context::new())
@@ -180,12 +161,6 @@ impl<T: Clone + Shift> Shift for Context<T> {
     }
 }
 
-impl Shift for NormalizationContext {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(NormalizationContext(self.0.shift(delta, var)?))
-    }
-}
-
 impl<T: Subst<Typed>> Subst<Typed> for CtxItem<T> {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
@@ -209,12 +184,6 @@ impl<T: Clone + Subst<Typed>> Subst<Typed> for Context<T> {
     }
 }
 
-impl Subst<Typed> for NormalizationContext {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        NormalizationContext(self.0.subst_shift(var, val))
-    }
-}
-
 impl PartialEq for TypecheckContext {
     fn eq(&self, _: &Self) -> bool {
         // don't count contexts when comparing stuff
diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 54a5442..87541d3 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -4,13 +4,11 @@ use std::rc::Rc;
 
 use dhall_syntax::{Const, ExprF};
 
-use crate::core::context::{NormalizationContext, TypecheckContext};
+use crate::core::context::TypecheckContext;
 use crate::core::value::Value;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
-use crate::phase::normalize::{
-    apply_any, normalize_one_layer, normalize_whnf, InputSubExpr, OutputSubExpr,
-};
+use crate::phase::normalize::{apply_any, normalize_one_layer, OutputSubExpr};
 use crate::phase::typecheck::type_of_const;
 use crate::phase::{Normalized, NormalizedSubExpr, Type, Typed};
 
@@ -25,8 +23,6 @@ use Marker::{NF, WHNF};
 
 #[derive(Debug)]
 enum ThunkInternal {
-    /// Non-normalized value alongside a normalization context
-    Unnormalized(NormalizationContext, InputSubExpr),
     /// Partially normalized value whose subexpressions have been thunked (this is returned from
     /// typechecking). Note that this is different from `Value::PartialExpr` because there is no
     /// requirement of WHNF here.
@@ -63,12 +59,6 @@ impl ThunkInternal {
 
     fn normalize_whnf(&mut self) {
         match self {
-            ThunkInternal::Unnormalized(ctx, e) => {
-                *self = ThunkInternal::Value(
-                    WHNF,
-                    normalize_whnf(ctx.clone(), e.clone()),
-                )
-            }
             ThunkInternal::PartialExpr(e) => {
                 *self =
                     ThunkInternal::Value(WHNF, normalize_one_layer(e.clone()))
@@ -80,8 +70,7 @@ impl ThunkInternal {
 
     fn normalize_nf(&mut self) {
         match self {
-            ThunkInternal::Unnormalized(_, _)
-            | ThunkInternal::PartialExpr(_) => {
+            ThunkInternal::PartialExpr(_) => {
                 self.normalize_whnf();
                 self.normalize_nf();
             }
@@ -97,8 +86,7 @@ impl ThunkInternal {
     // Always use normalize_whnf before
     fn as_whnf(&self) -> &Value {
         match self {
-            ThunkInternal::Unnormalized(_, _)
-            | ThunkInternal::PartialExpr(_) => unreachable!(),
+            ThunkInternal::PartialExpr(_) => unreachable!(),
             ThunkInternal::Value(_, v) => v,
         }
     }
@@ -106,19 +94,15 @@ impl ThunkInternal {
     // Always use normalize_nf before
     fn as_nf(&self) -> &Value {
         match self {
-            ThunkInternal::Unnormalized(_, _)
-            | ThunkInternal::PartialExpr(_)
-            | ThunkInternal::Value(WHNF, _) => unreachable!(),
+            ThunkInternal::PartialExpr(_) | ThunkInternal::Value(WHNF, _) => {
+                unreachable!()
+            }
             ThunkInternal::Value(NF, v) => v,
         }
     }
 }
 
 impl Thunk {
-    pub(crate) fn new(ctx: NormalizationContext, e: InputSubExpr) -> Thunk {
-        ThunkInternal::Unnormalized(ctx, e).into_thunk()
-    }
-
     pub(crate) fn from_value(v: Value) -> Thunk {
         ThunkInternal::Value(WHNF, v).into_thunk()
     }
@@ -141,8 +125,7 @@ impl Thunk {
     fn do_normalize_whnf(&self) {
         let borrow = self.0.borrow();
         match &*borrow {
-            ThunkInternal::Unnormalized(_, _)
-            | ThunkInternal::PartialExpr(_) => {
+            ThunkInternal::PartialExpr(_) => {
                 drop(borrow);
                 self.0.borrow_mut().normalize_whnf();
             }
@@ -154,9 +137,7 @@ impl Thunk {
     fn do_normalize_nf(&self) {
         let borrow = self.0.borrow();
         match &*borrow {
-            ThunkInternal::Unnormalized(_, _)
-            | ThunkInternal::PartialExpr(_)
-            | ThunkInternal::Value(WHNF, _) => {
+            ThunkInternal::PartialExpr(_) | ThunkInternal::Value(WHNF, _) => {
                 drop(borrow);
                 self.0.borrow_mut().normalize_nf();
             }
@@ -183,7 +164,10 @@ impl Thunk {
         self.as_value().clone()
     }
 
-    pub(crate) fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
         self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
@@ -222,7 +206,10 @@ impl TypedThunk {
         self.clone().into_typed()
     }
 
-    pub(crate) fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
         self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
@@ -302,9 +289,6 @@ impl Shift for Thunk {
 impl Shift for ThunkInternal {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
-            ThunkInternal::Unnormalized(ctx, e) => {
-                ThunkInternal::Unnormalized(ctx.shift(delta, var)?, e.clone())
-            }
             ThunkInternal::PartialExpr(e) => ThunkInternal::PartialExpr(
                 e.traverse_ref_with_special_handling_of_binders(
                     |v| Ok(v.shift(delta, var)?),
@@ -342,10 +326,6 @@ impl Subst<Typed> for Thunk {
 impl Subst<Typed> for ThunkInternal {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
-            ThunkInternal::Unnormalized(ctx, e) => ThunkInternal::Unnormalized(
-                ctx.subst_shift(var, val),
-                e.clone(),
-            ),
             ThunkInternal::PartialExpr(e) => ThunkInternal::PartialExpr(
                 e.map_ref_with_special_handling_of_binders(
                     |v| v.subst_shift(var, val),
@@ -404,11 +384,6 @@ impl std::fmt::Debug for Thunk {
             ThunkInternal::PartialExpr(e) => {
                 f.debug_tuple("Thunk@PartialExpr").field(e).finish()
             }
-            ThunkInternal::Unnormalized(ctx, e) => f
-                .debug_tuple("Thunk@Unnormalized")
-                .field(ctx)
-                .field(e)
-                .finish(),
         }
     }
 }
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 61a8eea..d3d017d 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -66,7 +66,10 @@ impl Value {
     }
     /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
     /// if alpha is `true`
-    pub(crate) fn normalize_to_expr_maybe_alpha(&self, alpha: bool) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
         match self {
             Value::Lam(x, t, e) => rc(ExprF::Lam(
                 x.to_label_maybe_alpha(alpha),
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index 4ef1b93..5e7bf05 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -61,12 +61,6 @@ impl AlphaVar {
             _ => self.normal.clone(),
         }
     }
-    pub(crate) fn from_var(normal: V<Label>) -> Self {
-        AlphaVar {
-            normal,
-            alpha: None,
-        }
-    }
     pub(crate) fn from_var_and_alpha(normal: V<Label>, alpha: usize) -> Self {
         AlphaVar {
             normal,
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 778f990..5a6d4db 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -76,11 +76,6 @@ impl Resolved {
     pub fn typecheck_with(self, ty: &Type) -> Result<Typed, TypeError> {
         typecheck::typecheck_with(self, ty)
     }
-    /// Pretends this expression has been typechecked. Use with care.
-    #[allow(dead_code)]
-    pub(crate) fn skip_typecheck(self) -> Typed {
-        typecheck::skip_typecheck(self)
-    }
 }
 
 impl Typed {
@@ -168,9 +163,6 @@ impl Normalized {
     pub(crate) fn to_type(&self) -> Type {
         self.0.to_type()
     }
-    pub(crate) fn to_value(&self) -> Value {
-        self.0.to_value()
-    }
     pub(crate) fn into_typed(self) -> Typed {
         self.0
     }
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index fd0197d..2a2bf3e 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -5,13 +5,11 @@ use dhall_syntax::{
     NaiveDouble,
 };
 
-use crate::core::context::NormalizationContext;
 use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
 use crate::core::var::{Shift, Subst};
-use crate::phase::{Normalized, NormalizedSubExpr, ResolvedSubExpr, Typed};
+use crate::phase::{Normalized, NormalizedSubExpr, Typed};
 
-pub(crate) type InputSubExpr = ResolvedSubExpr;
 pub(crate) type OutputSubExpr = NormalizedSubExpr;
 
 // Ad-hoc macro to help construct closures
@@ -381,24 +379,6 @@ pub(crate) fn squash_textlit(
     ret
 }
 
-/// Reduces the imput expression to a Value. Evaluates as little as possible.
-pub(crate) fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
-    match expr.as_ref() {
-        ExprF::Embed(e) => return e.to_value(),
-        ExprF::Var(v) => return ctx.lookup(v),
-        _ => {}
-    }
-
-    // Thunk subexpressions
-    let expr: ExprF<Thunk, Normalized> =
-        expr.as_ref().map_ref_with_special_handling_of_binders(
-            |e| Thunk::new(ctx.clone(), e.clone()),
-            |x, e| Thunk::new(ctx.skip(x), e.clone()),
-        );
-
-    normalize_one_layer(expr)
-}
-
 // Small helper enum to avoid repetition
 enum Ret<'a> {
     Value(Value),
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 7bbad38..dd6da70 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -4,7 +4,7 @@ use dhall_syntax::{
     rc, Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label, SubExpr,
 };
 
-use crate::core::context::{NormalizationContext, TypecheckContext};
+use crate::core::context::TypecheckContext;
 use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
 use crate::core::var::{Shift, Subst};
@@ -1009,11 +1009,11 @@ pub(crate) fn typecheck(e: Resolved) -> Result<Typed, TypeError> {
     type_of(e.0)
 }
 
-pub(crate) fn typecheck_with(e: Resolved, ty: &Type) -> Result<Typed, TypeError> {
+pub(crate) fn typecheck_with(
+    e: Resolved,
+    ty: &Type,
+) -> Result<Typed, TypeError> {
     let expr: SubExpr<_> = e.0;
     let ty: SubExpr<_> = ty.to_expr();
     type_of(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
 }
-pub(crate) fn skip_typecheck(e: Resolved) -> Typed {
-    Typed::from_thunk_untyped(Thunk::new(NormalizationContext::new(), e.0))
-}
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 71674a9..f400206 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -168,7 +168,8 @@ pub mod value {
         }
         pub(crate) fn make_optional_type(t: Value) -> Self {
             Self::from_dhall_value(
-                DhallValue::from_builtin(Builtin::Optional).app_thunk(t.to_thunk()),
+                DhallValue::from_builtin(Builtin::Optional)
+                    .app_thunk(t.to_thunk()),
             )
         }
         pub(crate) fn make_list_type(t: Value) -> Self {
-- 
cgit v1.3.1


From 1741bb9e3fe872b3b841a9f394de69c85f523ba5 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 18:34:05 +0200
Subject: No need for generic Context anymore

---
 dhall/src/core/context.rs | 113 ++++++++++++++++------------------------------
 1 file changed, 38 insertions(+), 75 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index 3c07c1c..36542d2 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -10,46 +10,46 @@ use crate::error::TypeError;
 use crate::phase::{Type, Typed};
 
 #[derive(Debug, Clone)]
-enum CtxItem<T> {
-    Kept(AlphaVar, T),
-    Replaced(Thunk, T),
+enum CtxItem {
+    Kept(AlphaVar, Type),
+    Replaced(Thunk, Type),
 }
 
 #[derive(Debug, Clone)]
-struct Context<T>(Rc<Vec<(Label, CtxItem<T>)>>);
+pub(crate) struct TypecheckContext(Rc<Vec<(Label, CtxItem)>>);
 
-#[derive(Debug, Clone)]
-pub(crate) struct TypecheckContext(Context<Type>);
-
-impl<T> Context<T> {
+impl TypecheckContext {
     pub fn new() -> Self {
-        Context(Rc::new(Vec::new()))
+        TypecheckContext(Rc::new(Vec::new()))
     }
-    pub fn insert_kept(&self, x: &Label, t: T) -> Self
-    where
-        T: Shift + Clone,
-    {
+    pub fn insert_type(&self, x: &Label, t: Type) -> Self {
         let mut vec = self.0.as_ref().clone();
         vec.push((x.clone(), CtxItem::Kept(x.into(), t.under_binder(x))));
-        Context(Rc::new(vec))
+        TypecheckContext(Rc::new(vec))
     }
-    pub fn insert_replaced(&self, x: &Label, th: Thunk, t: T) -> Self
-    where
-        T: Clone,
-    {
+    pub fn insert_value(&self, x: &Label, e: Typed) -> Result<Self, TypeError> {
         let mut vec = self.0.as_ref().clone();
-        vec.push((x.clone(), CtxItem::Replaced(th, t)));
-        Context(Rc::new(vec))
+        vec.push((
+            x.clone(),
+            CtxItem::Replaced(e.to_thunk(), e.get_type()?.into_owned()),
+        ));
+        Ok(TypecheckContext(Rc::new(vec)))
     }
-    pub fn lookup(&self, var: &V<Label>) -> Result<CtxItem<T>, V<Label>>
-    where
-        T: Clone + Shift,
-    {
+    pub fn lookup(&self, var: &V<Label>) -> Option<Typed> {
         let mut var = var.clone();
         let mut shift_map: HashMap<Label, _> = HashMap::new();
         for (l, i) in self.0.iter().rev() {
             match var.over_binder(l) {
-                None => return Ok(i.under_multiple_binders(&shift_map)),
+                None => {
+                    let i = i.under_multiple_binders(&shift_map);
+                    let (th, t) = match i {
+                        CtxItem::Kept(newvar, t) => {
+                            (Value::Var(newvar).into_thunk(), t)
+                        }
+                        CtxItem::Replaced(th, t) => (th, t),
+                    };
+                    return Some(Typed::from_thunk_and_type(th, t));
+                }
                 Some(newvar) => var = newvar,
             };
             if let CtxItem::Kept(_, _) = i {
@@ -57,7 +57,7 @@ impl<T> Context<T> {
             }
         }
         // Free variable
-        Err(var)
+        None
     }
     /// Given a var that makes sense in the current context, map the given function in such a way
     /// that the passed variable always makes sense in the context of the passed item.
@@ -66,11 +66,8 @@ impl<T> Context<T> {
     fn do_with_var<E>(
         &self,
         var: &AlphaVar,
-        mut f: impl FnMut(&AlphaVar, &CtxItem<T>) -> Result<CtxItem<T>, E>,
-    ) -> Result<Self, E>
-    where
-        T: Clone,
-    {
+        mut f: impl FnMut(&AlphaVar, &CtxItem) -> Result<CtxItem, E>,
+    ) -> Result<Self, E> {
         let mut vec = Vec::new();
         vec.reserve(self.0.len());
         let mut var = var.clone();
@@ -88,16 +85,13 @@ impl<T> Context<T> {
             vec.push((l.clone(), (*i).clone()));
         }
         vec.reverse();
-        Ok(Context(Rc::new(vec)))
+        Ok(TypecheckContext(Rc::new(vec)))
     }
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self>
-    where
-        T: Clone + Shift,
-    {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         if delta < 0 {
             Some(self.do_with_var(var, |var, i| Ok(i.shift(delta, &var)?))?)
         } else {
-            Some(Context(Rc::new(
+            Some(TypecheckContext(Rc::new(
                 self.0
                     .iter()
                     .map(|(l, i)| Ok((l.clone(), i.shift(delta, &var)?)))
@@ -105,44 +99,13 @@ impl<T> Context<T> {
             )))
         }
     }
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self
-    where
-        T: Clone + Subst<Typed>,
-    {
+    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         self.do_with_var(var, |var, i| Ok::<_, !>(i.subst_shift(&var, val)))
             .unwrap()
     }
 }
 
-impl TypecheckContext {
-    pub fn new() -> Self {
-        TypecheckContext(Context::new())
-    }
-    pub fn insert_type(&self, x: &Label, t: Type) -> Self {
-        TypecheckContext(self.0.insert_kept(x, t))
-    }
-    pub fn insert_value(&self, x: &Label, e: Typed) -> Result<Self, TypeError> {
-        Ok(TypecheckContext(self.0.insert_replaced(
-            x,
-            e.to_thunk(),
-            e.get_type()?.into_owned(),
-        )))
-    }
-    pub fn lookup(&self, var: &V<Label>) -> Option<Typed> {
-        match self.0.lookup(var) {
-            Ok(CtxItem::Kept(newvar, t)) => Some(Typed::from_thunk_and_type(
-                Thunk::from_value(Value::Var(newvar.clone())),
-                t.clone(),
-            )),
-            Ok(CtxItem::Replaced(th, t)) => {
-                Some(Typed::from_thunk_and_type(th.clone(), t.clone()))
-            }
-            Err(_) => None,
-        }
-    }
-}
-
-impl<T: Shift> Shift for CtxItem<T> {
+impl Shift for CtxItem {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
             CtxItem::Kept(v, t) => {
@@ -155,13 +118,13 @@ impl<T: Shift> Shift for CtxItem<T> {
     }
 }
 
-impl<T: Clone + Shift> Shift for Context<T> {
+impl Shift for TypecheckContext {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         self.shift(delta, var)
     }
 }
 
-impl<T: Subst<Typed>> Subst<Typed> for CtxItem<T> {
+impl Subst<Typed> for CtxItem {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
             CtxItem::Replaced(e, t) => CtxItem::Replaced(
@@ -178,16 +141,16 @@ impl<T: Subst<Typed>> Subst<Typed> for CtxItem<T> {
     }
 }
 
-impl<T: Clone + Subst<Typed>> Subst<Typed> for Context<T> {
+impl Subst<Typed> for TypecheckContext {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         self.subst_shift(var, val)
     }
 }
 
+/// Don't count contexts when comparing stuff.
+/// This is dirty but needed.
 impl PartialEq for TypecheckContext {
     fn eq(&self, _: &Self) -> bool {
-        // don't count contexts when comparing stuff
-        // this is dirty but needed for now
         true
     }
 }
-- 
cgit v1.3.1


From 9babfb33ab95a93d1e2b70c54ee8100409253ce9 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 18:40:36 +0200
Subject: Free variables don't exist anymore

---
 dhall/src/core/var.rs | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index 5e7bf05..becd653 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -2,13 +2,13 @@ use std::collections::HashMap;
 
 use dhall_syntax::{Label, V};
 
-/// Stores a pair of variables: a normal one and if relevant one
+/// Stores a pair of variables: a normal one and one
 /// that corresponds to the alpha-normalized version of the first one.
-/// Equality is up to alpha-equivalence.
+/// Equality is up to alpha-equivalence (compares on the second one only).
 #[derive(Clone, Eq)]
 pub struct AlphaVar {
     normal: V<Label>,
-    alpha: Option<V<()>>,
+    alpha: V<()>,
 }
 
 // Exactly like a Label, but equality returns always true.
@@ -56,15 +56,16 @@ pub(crate) trait Subst<T> {
 
 impl AlphaVar {
     pub(crate) fn to_var(&self, alpha: bool) -> V<Label> {
-        match (alpha, &self.alpha) {
-            (true, Some(x)) => V("_".into(), x.1),
-            _ => self.normal.clone(),
+        if alpha {
+            V("_".into(), self.alpha.1)
+        } else {
+            self.normal.clone()
         }
     }
     pub(crate) fn from_var_and_alpha(normal: V<Label>, alpha: usize) -> Self {
         AlphaVar {
             normal,
-            alpha: Some(V((), alpha)),
+            alpha: V((), alpha),
         }
     }
 }
@@ -86,10 +87,7 @@ impl Shift for AlphaVar {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(AlphaVar {
             normal: self.normal.shift(delta, &var.normal)?,
-            alpha: match (&self.alpha, &var.alpha) {
-                (Some(x), Some(v)) => Some(x.shift(delta, v)?),
-                _ => None,
-            },
+            alpha: self.alpha.shift(delta, &var.alpha)?,
         })
     }
 }
@@ -104,13 +102,10 @@ impl<T> Subst<T> for () {
     fn subst_shift(&self, _var: &AlphaVar, _val: &T) -> Self {}
 }
 
+/// Equality up to alpha-equivalence
 impl std::cmp::PartialEq for AlphaVar {
     fn eq(&self, other: &Self) -> bool {
-        match (&self.alpha, &other.alpha) {
-            (Some(x), Some(y)) => x == y,
-            (None, None) => self.normal == other.normal,
-            _ => false,
-        }
+        self.alpha == other.alpha
     }
 }
 impl std::cmp::PartialEq for AlphaLabel {
@@ -121,10 +116,7 @@ impl std::cmp::PartialEq for AlphaLabel {
 
 impl std::fmt::Debug for AlphaVar {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match &self.alpha {
-            Some(a) => write!(f, "AlphaVar({}, {})", self.normal, a.1),
-            None => write!(f, "AlphaVar({}, free)", self.normal),
-        }
+        write!(f, "AlphaVar({}, {})", self.normal, self.alpha.1)
     }
 }
 
@@ -138,7 +130,7 @@ impl From<Label> for AlphaVar {
     fn from(x: Label) -> AlphaVar {
         AlphaVar {
             normal: V(x, 0),
-            alpha: Some(V((), 0)),
+            alpha: V((), 0),
         }
     }
 }
-- 
cgit v1.3.1


From fcc9afb3624883c4f99320c37678b7f9d338630d Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 18:41:19 +0200
Subject: fixup! No need for generic Context anymore

---
 dhall/src/core/context.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index 36542d2..cc25749 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -56,7 +56,7 @@ impl TypecheckContext {
                 *shift_map.entry(l.clone()).or_insert(0) += 1;
             }
         }
-        // Free variable
+        // Unbound variable
         None
     }
     /// Given a var that makes sense in the current context, map the given function in such a way
-- 
cgit v1.3.1


From 45fb07f74f19919f742be6fe7793dc72d4022f26 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 19:16:40 +0200
Subject: Try to minimize untyped TypedThunks

---
 dhall/src/core/thunk.rs      | 13 +++++------
 dhall/src/phase/mod.rs       |  7 ++++--
 dhall/src/phase/normalize.rs | 54 +++++++++++++++++++++++++-------------------
 serde_dhall/src/lib.rs       | 24 ++++++++++++--------
 4 files changed, 57 insertions(+), 41 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 87541d3..5f96ec8 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -182,11 +182,7 @@ impl Thunk {
 
 impl TypedThunk {
     pub(crate) fn from_value(v: Value) -> TypedThunk {
-        TypedThunk::from_thunk(Thunk::from_value(v))
-    }
-
-    pub fn from_thunk(th: Thunk) -> TypedThunk {
-        TypedThunk::from_thunk_untyped(th)
+        TypedThunk::from_thunk_untyped(Thunk::from_value(v))
     }
 
     pub(crate) fn from_type(t: Type) -> TypedThunk {
@@ -216,14 +212,17 @@ impl TypedThunk {
     pub(crate) fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
         TypedThunk::Typed(th, Box::new(t))
     }
+    pub fn from_thunk_simple_type(th: Thunk) -> Self {
+        TypedThunk::from_thunk_and_type(th, Type::const_type())
+    }
     pub(crate) fn from_thunk_untyped(th: Thunk) -> Self {
         TypedThunk::Untyped(th)
     }
     pub(crate) fn from_const(c: Const) -> Self {
         TypedThunk::Const(c)
     }
-    pub(crate) fn from_value_untyped(v: Value) -> Self {
-        TypedThunk::from_thunk_untyped(Thunk::from_value(v))
+    pub(crate) fn from_value_and_type(v: Value, t: Type) -> Self {
+        TypedThunk::from_thunk_and_type(Thunk::from_value(v), t)
     }
 
     // TODO: Avoid cloning if possible
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 5a6d4db..adf749c 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -101,12 +101,15 @@ impl Typed {
     pub(crate) fn from_const(c: Const) -> Self {
         Typed(TypedThunk::from_const(c))
     }
-    pub fn from_value_untyped(v: Value) -> Self {
-        Typed(TypedThunk::from_value_untyped(v))
+    pub fn from_value_and_type(v: Value, t: Type) -> Self {
+        Typed(TypedThunk::from_value_and_type(v, t))
     }
     pub(crate) fn from_typethunk(th: TypedThunk) -> Self {
         Typed(th)
     }
+    pub fn const_type() -> Self {
+        Typed::from_const(Const::Type)
+    }
 
     pub(crate) fn to_value(&self) -> Value {
         self.0.to_value()
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 2a2bf3e..02b705d 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -22,10 +22,13 @@ macro_rules! make_closure {
         );
         Value::Var(var).into_thunk()
     }};
+    // Warning: assumes that $ty, as a dhall value, has type `Type`
     (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
         Value::Lam(
             Label::from(stringify!($var)).into(),
-            TypedThunk::from_thunk_untyped(make_closure!($($ty)*)),
+            TypedThunk::from_thunk_simple_type(
+                make_closure!($($ty)*),
+            ),
             make_closure!($($rest)*),
         ).into_thunk()
     };
@@ -61,9 +64,10 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
 
     // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
     let ret = match (b, args.as_slice()) {
-        (OptionalNone, [t, r..]) => {
-            Ok((r, EmptyOptionalLit(TypedThunk::from_thunk(t.clone()))))
-        }
+        (OptionalNone, [t, r..]) => Ok((
+            r,
+            EmptyOptionalLit(TypedThunk::from_thunk_simple_type(t.clone())),
+        )),
         (NaturalIsZero, [n, r..]) => match &*n.as_value() {
             NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
             _ => Err(()),
@@ -228,7 +232,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                             [ var(x, 1) ] # var(xs, 0)
                         )
                     })
-                    .app_val(EmptyListLit(TypedThunk::from_thunk(t.clone()))),
+                    .app_val(EmptyListLit(TypedThunk::from_thunk_simple_type(
+                        t.clone(),
+                    ))),
             )),
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_value() {
@@ -260,9 +266,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                 r,
                 f.app_val(Value::from_builtin(Optional).app_thunk(t.clone()))
                     .app_thunk(make_closure!(λ(x: #t) -> Some var(x, 0)))
-                    .app_val(EmptyOptionalLit(TypedThunk::from_thunk(
-                        t.clone(),
-                    ))),
+                    .app_val(EmptyOptionalLit(
+                        TypedThunk::from_thunk_simple_type(t.clone()),
+                    )),
             )),
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_value() {
@@ -611,18 +617,20 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         }
         (RecursiveRecordTypeMerge, RecordType(kvs1), RecordType(kvs2)) => {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
-                TypedThunk::from_thunk(Thunk::from_partial_expr(ExprF::BinOp(
-                    RecursiveRecordTypeMerge,
-                    v1.to_thunk(),
-                    v2.to_thunk(),
-                )))
+                TypedThunk::from_thunk_untyped(Thunk::from_partial_expr(
+                    ExprF::BinOp(
+                        RecursiveRecordTypeMerge,
+                        v1.to_thunk(),
+                        v2.to_thunk(),
+                    ),
+                ))
             });
             Ret::Value(RecordType(kvs))
         }
 
         (Equivalence, _, _) => Ret::Value(Value::Equivalence(
-            TypedThunk::from_thunk(x.clone()),
-            TypedThunk::from_thunk(y.clone()),
+            TypedThunk::from_thunk_simple_type(x.clone()),
+            TypedThunk::from_thunk_simple_type(y.clone()),
         )),
 
         _ => return None,
@@ -645,12 +653,12 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
         ExprF::Annot(x, _) => Ret::Thunk(x),
         ExprF::Assert(_) => Ret::Expr(expr),
         ExprF::Lam(x, t, e) => {
-            Ret::Value(Lam(x.into(), TypedThunk::from_thunk(t), e))
+            Ret::Value(Lam(x.into(), TypedThunk::from_thunk_untyped(t), e))
         }
         ExprF::Pi(x, t, e) => Ret::Value(Pi(
             x.into(),
-            TypedThunk::from_thunk(t),
-            TypedThunk::from_thunk(e),
+            TypedThunk::from_thunk_untyped(t),
+            TypedThunk::from_thunk_untyped(e),
         )),
         ExprF::Let(x, _, v, b) => {
             let v = Typed::from_thunk_untyped(v);
@@ -669,9 +677,9 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
             let t_borrow = t.as_value();
             match &*t_borrow {
                 AppliedBuiltin(Builtin::List, args) if args.len() == 1 => {
-                    Ret::Value(EmptyListLit(TypedThunk::from_thunk(
-                        args[0].clone(),
-                    )))
+                    Ret::Value(EmptyListLit(
+                        TypedThunk::from_thunk_simple_type(args[0].clone()),
+                    ))
                 }
                 _ => {
                     drop(t_borrow);
@@ -687,12 +695,12 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
         }
         ExprF::RecordType(kts) => Ret::Value(RecordType(
             kts.into_iter()
-                .map(|(k, t)| (k, TypedThunk::from_thunk(t)))
+                .map(|(k, t)| (k, TypedThunk::from_thunk_untyped(t)))
                 .collect(),
         )),
         ExprF::UnionType(kts) => Ret::Value(UnionType(
             kts.into_iter()
-                .map(|(k, t)| (k, t.map(|t| TypedThunk::from_thunk(t))))
+                .map(|(k, t)| (k, t.map(|t| TypedThunk::from_thunk_untyped(t))))
                 .collect(),
         )),
         ExprF::TextLit(elts) => {
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index f400206..a277977 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -160,20 +160,21 @@ pub mod value {
             self.0.to_type()
         }
 
-        pub(crate) fn from_dhall_value(v: DhallValue) -> Self {
-            Value(Typed::from_value_untyped(v))
+        /// Assumes that the given value has type `Type`.
+        pub(crate) fn make_simple_type(v: DhallValue) -> Self {
+            Value(Typed::from_value_and_type(v, Type::const_type()))
         }
         pub(crate) fn make_builtin_type(b: Builtin) -> Self {
-            Self::from_dhall_value(DhallValue::from_builtin(b))
+            Self::make_simple_type(DhallValue::from_builtin(b))
         }
         pub(crate) fn make_optional_type(t: Value) -> Self {
-            Self::from_dhall_value(
+            Self::make_simple_type(
                 DhallValue::from_builtin(Builtin::Optional)
                     .app_thunk(t.to_thunk()),
             )
         }
         pub(crate) fn make_list_type(t: Value) -> Self {
-            Self::from_dhall_value(
+            Self::make_simple_type(
                 DhallValue::from_builtin(Builtin::List).app_thunk(t.to_thunk()),
             )
         }
@@ -182,9 +183,9 @@ pub mod value {
         pub fn make_record_type(
             kts: impl Iterator<Item = (String, Value)>,
         ) -> Self {
-            Self::from_dhall_value(DhallValue::RecordType(
+            Self::make_simple_type(DhallValue::RecordType(
                 kts.map(|(k, t)| {
-                    (k.into(), TypedThunk::from_thunk(t.to_thunk()))
+                    (k.into(), TypedThunk::from_thunk_simple_type(t.to_thunk()))
                 })
                 .collect(),
             ))
@@ -193,9 +194,14 @@ pub mod value {
         pub fn make_union_type(
             kts: impl Iterator<Item = (String, Option<Value>)>,
         ) -> Self {
-            Self::from_dhall_value(DhallValue::UnionType(
+            Self::make_simple_type(DhallValue::UnionType(
                 kts.map(|(k, t)| {
-                    (k.into(), t.map(|t| TypedThunk::from_thunk(t.to_thunk())))
+                    (
+                        k.into(),
+                        t.map(|t| {
+                            TypedThunk::from_thunk_simple_type(t.to_thunk())
+                        }),
+                    )
                 })
                 .collect(),
             ))
-- 
cgit v1.3.1


From e0f5216215ccb7a4df85d80e11dd265cdb52a44f Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 19:47:36 +0200
Subject: s/Value/ValueF/

---
 dhall/src/core/context.rs    |   4 +-
 dhall/src/core/thunk.rs      |  90 ++++++++--------
 dhall/src/core/value.rs      | 212 ++++++++++++++++++------------------
 dhall/src/core/var.rs        |   2 +-
 dhall/src/phase/mod.rs       |  12 +--
 dhall/src/phase/normalize.rs | 250 ++++++++++++++++++++++---------------------
 dhall/src/phase/typecheck.rs | 110 +++++++++----------
 serde_dhall/src/lib.rs       |   4 +-
 8 files changed, 345 insertions(+), 339 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index cc25749..b1fbde9 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -4,7 +4,7 @@ use std::rc::Rc;
 use dhall_syntax::{Label, V};
 
 use crate::core::thunk::Thunk;
-use crate::core::value::Value;
+use crate::core::value::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::TypeError;
 use crate::phase::{Type, Typed};
@@ -44,7 +44,7 @@ impl TypecheckContext {
                     let i = i.under_multiple_binders(&shift_map);
                     let (th, t) = match i {
                         CtxItem::Kept(newvar, t) => {
-                            (Value::Var(newvar).into_thunk(), t)
+                            (ValueF::Var(newvar).into_thunk(), t)
                         }
                         CtxItem::Replaced(th, t) => (th, t),
                     };
diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index 5f96ec8..cf7c097 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -5,7 +5,7 @@ use std::rc::Rc;
 use dhall_syntax::{Const, ExprF};
 
 use crate::core::context::TypecheckContext;
-use crate::core::value::Value;
+use crate::core::value::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::normalize::{apply_any, normalize_one_layer, OutputSubExpr};
@@ -24,12 +24,12 @@ use Marker::{NF, WHNF};
 #[derive(Debug)]
 enum ThunkInternal {
     /// Partially normalized value whose subexpressions have been thunked (this is returned from
-    /// typechecking). Note that this is different from `Value::PartialExpr` because there is no
+    /// typechecking). Note that this is different from `ValueF::PartialExpr` because there is no
     /// requirement of WHNF here.
     PartialExpr(ExprF<Thunk, Normalized>),
     /// Partially normalized value.
     /// Invariant: if the marker is `NF`, the value must be fully normalized
-    Value(Marker, Value),
+    ValueF(Marker, ValueF),
 }
 
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
@@ -61,10 +61,10 @@ impl ThunkInternal {
         match self {
             ThunkInternal::PartialExpr(e) => {
                 *self =
-                    ThunkInternal::Value(WHNF, normalize_one_layer(e.clone()))
+                    ThunkInternal::ValueF(WHNF, normalize_one_layer(e.clone()))
             }
             // Already at least in WHNF
-            ThunkInternal::Value(_, _) => {}
+            ThunkInternal::ValueF(_, _) => {}
         }
     }
 
@@ -74,37 +74,37 @@ impl ThunkInternal {
                 self.normalize_whnf();
                 self.normalize_nf();
             }
-            ThunkInternal::Value(m @ WHNF, v) => {
+            ThunkInternal::ValueF(m @ WHNF, v) => {
                 v.normalize_mut();
                 *m = NF;
             }
             // Already in NF
-            ThunkInternal::Value(NF, _) => {}
+            ThunkInternal::ValueF(NF, _) => {}
         }
     }
 
     // Always use normalize_whnf before
-    fn as_whnf(&self) -> &Value {
+    fn as_whnf(&self) -> &ValueF {
         match self {
             ThunkInternal::PartialExpr(_) => unreachable!(),
-            ThunkInternal::Value(_, v) => v,
+            ThunkInternal::ValueF(_, v) => v,
         }
     }
 
     // Always use normalize_nf before
-    fn as_nf(&self) -> &Value {
+    fn as_nf(&self) -> &ValueF {
         match self {
-            ThunkInternal::PartialExpr(_) | ThunkInternal::Value(WHNF, _) => {
+            ThunkInternal::PartialExpr(_) | ThunkInternal::ValueF(WHNF, _) => {
                 unreachable!()
             }
-            ThunkInternal::Value(NF, v) => v,
+            ThunkInternal::ValueF(NF, v) => v,
         }
     }
 }
 
 impl Thunk {
-    pub(crate) fn from_value(v: Value) -> Thunk {
-        ThunkInternal::Value(WHNF, v).into_thunk()
+    pub(crate) fn from_valuef(v: ValueF) -> Thunk {
+        ThunkInternal::ValueF(WHNF, v).into_thunk()
     }
 
     pub(crate) fn from_partial_expr(e: ExprF<Thunk, Normalized>) -> Thunk {
@@ -130,38 +130,38 @@ impl Thunk {
                 self.0.borrow_mut().normalize_whnf();
             }
             // Already at least in WHNF
-            ThunkInternal::Value(_, _) => {}
+            ThunkInternal::ValueF(_, _) => {}
         }
     }
 
     fn do_normalize_nf(&self) {
         let borrow = self.0.borrow();
         match &*borrow {
-            ThunkInternal::PartialExpr(_) | ThunkInternal::Value(WHNF, _) => {
+            ThunkInternal::PartialExpr(_) | ThunkInternal::ValueF(WHNF, _) => {
                 drop(borrow);
                 self.0.borrow_mut().normalize_nf();
             }
             // Already in NF
-            ThunkInternal::Value(NF, _) => {}
+            ThunkInternal::ValueF(NF, _) => {}
         }
     }
 
     // WARNING: avoid normalizing any thunk while holding on to this ref
     // or you could run into BorrowMut panics
-    pub(crate) fn normalize_nf(&self) -> Ref<Value> {
+    pub(crate) fn normalize_nf(&self) -> Ref<ValueF> {
         self.do_normalize_nf();
         Ref::map(self.0.borrow(), ThunkInternal::as_nf)
     }
 
     // WARNING: avoid normalizing any thunk while holding on to this ref
     // or you could run into BorrowMut panics
-    pub(crate) fn as_value(&self) -> Ref<Value> {
+    pub(crate) fn as_valuef(&self) -> Ref<ValueF> {
         self.do_normalize_whnf();
         Ref::map(self.0.borrow(), ThunkInternal::as_whnf)
     }
 
-    pub(crate) fn to_value(&self) -> Value {
-        self.as_value().clone()
+    pub(crate) fn to_valuef(&self) -> ValueF {
+        self.as_valuef().clone()
     }
 
     pub(crate) fn normalize_to_expr_maybe_alpha(
@@ -171,27 +171,27 @@ impl Thunk {
         self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub(crate) fn app_val(&self, val: Value) -> Value {
+    pub(crate) fn app_val(&self, val: ValueF) -> ValueF {
         self.app_thunk(val.into_thunk())
     }
 
-    pub(crate) fn app_thunk(&self, th: Thunk) -> Value {
+    pub(crate) fn app_thunk(&self, th: Thunk) -> ValueF {
         apply_any(self.clone(), th)
     }
 }
 
 impl TypedThunk {
-    pub(crate) fn from_value(v: Value) -> TypedThunk {
-        TypedThunk::from_thunk_untyped(Thunk::from_value(v))
+    pub(crate) fn from_valuef(v: ValueF) -> TypedThunk {
+        TypedThunk::from_thunk_untyped(Thunk::from_valuef(v))
     }
 
     pub(crate) fn from_type(t: Type) -> TypedThunk {
         t.into_typethunk()
     }
 
-    pub(crate) fn normalize_nf(&self) -> Value {
+    pub(crate) fn normalize_nf(&self) -> ValueF {
         match self {
-            TypedThunk::Const(c) => Value::Const(*c),
+            TypedThunk::Const(c) => ValueF::Const(*c),
             TypedThunk::Untyped(thunk) | TypedThunk::Typed(thunk, _) => {
                 thunk.normalize_nf().clone()
             }
@@ -221,27 +221,29 @@ impl TypedThunk {
     pub(crate) fn from_const(c: Const) -> Self {
         TypedThunk::Const(c)
     }
-    pub(crate) fn from_value_and_type(v: Value, t: Type) -> Self {
-        TypedThunk::from_thunk_and_type(Thunk::from_value(v), t)
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
+        TypedThunk::from_thunk_and_type(Thunk::from_valuef(v), t)
     }
 
     // TODO: Avoid cloning if possible
-    pub(crate) fn to_value(&self) -> Value {
+    pub(crate) fn to_valuef(&self) -> ValueF {
         match self {
-            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.to_value(),
-            TypedThunk::Const(c) => Value::Const(*c),
+            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => {
+                th.to_valuef()
+            }
+            TypedThunk::Const(c) => ValueF::Const(*c),
         }
     }
     pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
-        self.to_value().normalize_to_expr()
+        self.to_valuef().normalize_to_expr()
     }
     pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
-        self.to_value().normalize_to_expr_maybe_alpha(true)
+        self.to_valuef().normalize_to_expr_maybe_alpha(true)
     }
     pub(crate) fn to_thunk(&self) -> Thunk {
         match self {
             TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.clone(),
-            TypedThunk::Const(c) => Thunk::from_value(Value::Const(*c)),
+            TypedThunk::Const(c) => Thunk::from_valuef(ValueF::Const(*c)),
         }
     }
     pub(crate) fn to_type(&self) -> Type {
@@ -252,8 +254,8 @@ impl TypedThunk {
     }
     pub(crate) fn as_const(&self) -> Option<Const> {
         // TODO: avoid clone
-        match &self.to_value() {
-            Value::Const(c) => Some(*c),
+        match &self.to_valuef() {
+            ValueF::Const(c) => Some(*c),
             _ => None,
         }
     }
@@ -294,8 +296,8 @@ impl Shift for ThunkInternal {
                     |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
                 )?,
             ),
-            ThunkInternal::Value(m, v) => {
-                ThunkInternal::Value(*m, v.shift(delta, var)?)
+            ThunkInternal::ValueF(m, v) => {
+                ThunkInternal::ValueF(*m, v.shift(delta, var)?)
             }
         })
     }
@@ -336,9 +338,9 @@ impl Subst<Typed> for ThunkInternal {
                     },
                 ),
             ),
-            ThunkInternal::Value(_, v) => {
+            ThunkInternal::ValueF(_, v) => {
                 // The resulting value may not stay in normal form after substitution
-                ThunkInternal::Value(WHNF, v.subst_shift(var, val))
+                ThunkInternal::ValueF(WHNF, v.subst_shift(var, val))
             }
         }
     }
@@ -361,14 +363,14 @@ impl Subst<Typed> for TypedThunk {
 
 impl std::cmp::PartialEq for Thunk {
     fn eq(&self, other: &Self) -> bool {
-        *self.as_value() == *other.as_value()
+        *self.as_valuef() == *other.as_valuef()
     }
 }
 impl std::cmp::Eq for Thunk {}
 
 impl std::cmp::PartialEq for TypedThunk {
     fn eq(&self, other: &Self) -> bool {
-        self.to_value() == other.to_value()
+        self.to_valuef() == other.to_valuef()
     }
 }
 impl std::cmp::Eq for TypedThunk {}
@@ -377,7 +379,7 @@ impl std::fmt::Debug for Thunk {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let b: &ThunkInternal = &self.0.borrow();
         match b {
-            ThunkInternal::Value(m, v) => {
+            ThunkInternal::ValueF(m, v) => {
                 f.debug_tuple(&format!("Thunk@{:?}", m)).field(v).finish()
             }
             ThunkInternal::PartialExpr(e) => {
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index d3d017d..0f2ef00 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -15,16 +15,16 @@ use crate::phase::{Normalized, Typed};
 /// A semantic value. The invariants ensure this value represents a Weak-Head
 /// Normal Form (WHNF). This means that this first constructor is the first constructor of the
 /// final Normal Form (NF).
-/// This WHNF must be preserved by operations on `Value`s. In particular, `subst_shift` could break
+/// This WHNF must be preserved by operations on `ValueF`s. In particular, `subst_shift` could break
 /// the invariants so need to be careful to reevaluate as needed.
 /// Subexpressions are Thunks, which are partially evaluated expressions that are normalized
-/// on-demand. When all the Thunks in a Value are at least in WHNF, and recursively so, then the
-/// Value is in NF. This is because WHNF ensures that we have the first constructor of the NF; so
+/// on-demand. When all the Thunks in a ValueF are at least in WHNF, and recursively so, then the
+/// ValueF is in NF. This is because WHNF ensures that we have the first constructor of the NF; so
 /// if we have the first constructor of the NF at all levels, we actually have the NF.
 /// Equality is up to alpha-equivalence (renaming of bound variables) and beta-equivalence
 /// (normalization). Equality will normalize only as needed.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub enum Value {
+pub enum ValueF {
     /// Closures
     Lam(AlphaLabel, TypedThunk, Thunk),
     Pi(AlphaLabel, TypedThunk, TypedThunk),
@@ -55,9 +55,9 @@ pub enum Value {
     PartialExpr(ExprF<Thunk, Normalized>),
 }
 
-impl Value {
+impl ValueF {
     pub(crate) fn into_thunk(self) -> Thunk {
-        Thunk::from_value(self)
+        Thunk::from_valuef(self)
     }
 
     /// Convert the value to a fully normalized syntactic expression
@@ -71,12 +71,12 @@ impl Value {
         alpha: bool,
     ) -> OutputSubExpr {
         match self {
-            Value::Lam(x, t, e) => rc(ExprF::Lam(
+            ValueF::Lam(x, t, e) => rc(ExprF::Lam(
                 x.to_label_maybe_alpha(alpha),
                 t.normalize_to_expr_maybe_alpha(alpha),
                 e.normalize_to_expr_maybe_alpha(alpha),
             )),
-            Value::AppliedBuiltin(b, args) => {
+            ValueF::AppliedBuiltin(b, args) => {
                 let mut e = rc(ExprF::Builtin(*b));
                 for v in args {
                     e = rc(ExprF::App(
@@ -86,48 +86,48 @@ impl Value {
                 }
                 e
             }
-            Value::Pi(x, t, e) => rc(ExprF::Pi(
+            ValueF::Pi(x, t, e) => rc(ExprF::Pi(
                 x.to_label_maybe_alpha(alpha),
                 t.normalize_to_expr_maybe_alpha(alpha),
                 e.normalize_to_expr_maybe_alpha(alpha),
             )),
-            Value::Var(v) => rc(ExprF::Var(v.to_var(alpha))),
-            Value::Const(c) => rc(ExprF::Const(*c)),
-            Value::BoolLit(b) => rc(ExprF::BoolLit(*b)),
-            Value::NaturalLit(n) => rc(ExprF::NaturalLit(*n)),
-            Value::IntegerLit(n) => rc(ExprF::IntegerLit(*n)),
-            Value::DoubleLit(n) => rc(ExprF::DoubleLit(*n)),
-            Value::EmptyOptionalLit(n) => rc(ExprF::App(
+            ValueF::Var(v) => rc(ExprF::Var(v.to_var(alpha))),
+            ValueF::Const(c) => rc(ExprF::Const(*c)),
+            ValueF::BoolLit(b) => rc(ExprF::BoolLit(*b)),
+            ValueF::NaturalLit(n) => rc(ExprF::NaturalLit(*n)),
+            ValueF::IntegerLit(n) => rc(ExprF::IntegerLit(*n)),
+            ValueF::DoubleLit(n) => rc(ExprF::DoubleLit(*n)),
+            ValueF::EmptyOptionalLit(n) => rc(ExprF::App(
                 rc(ExprF::Builtin(Builtin::OptionalNone)),
                 n.normalize_to_expr_maybe_alpha(alpha),
             )),
-            Value::NEOptionalLit(n) => {
+            ValueF::NEOptionalLit(n) => {
                 rc(ExprF::SomeLit(n.normalize_to_expr_maybe_alpha(alpha)))
             }
-            Value::EmptyListLit(n) => rc(ExprF::EmptyListLit(rc(ExprF::App(
+            ValueF::EmptyListLit(n) => rc(ExprF::EmptyListLit(rc(ExprF::App(
                 rc(ExprF::Builtin(Builtin::List)),
                 n.normalize_to_expr_maybe_alpha(alpha),
             )))),
-            Value::NEListLit(elts) => rc(ExprF::NEListLit(
+            ValueF::NEListLit(elts) => rc(ExprF::NEListLit(
                 elts.iter()
                     .map(|n| n.normalize_to_expr_maybe_alpha(alpha))
                     .collect(),
             )),
-            Value::RecordLit(kvs) => rc(ExprF::RecordLit(
+            ValueF::RecordLit(kvs) => rc(ExprF::RecordLit(
                 kvs.iter()
                     .map(|(k, v)| {
                         (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
                     })
                     .collect(),
             )),
-            Value::RecordType(kts) => rc(ExprF::RecordType(
+            ValueF::RecordType(kts) => rc(ExprF::RecordType(
                 kts.iter()
                     .map(|(k, v)| {
                         (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
                     })
                     .collect(),
             )),
-            Value::UnionType(kts) => rc(ExprF::UnionType(
+            ValueF::UnionType(kts) => rc(ExprF::UnionType(
                 kts.iter()
                     .map(|(k, v)| {
                         (
@@ -139,7 +139,7 @@ impl Value {
                     })
                     .collect(),
             )),
-            Value::UnionConstructor(l, kts) => {
+            ValueF::UnionConstructor(l, kts) => {
                 let kts = kts
                     .iter()
                     .map(|(k, v)| {
@@ -153,12 +153,12 @@ impl Value {
                     .collect();
                 rc(ExprF::Field(rc(ExprF::UnionType(kts)), l.clone()))
             }
-            Value::UnionLit(l, v, kts) => rc(ExprF::App(
-                Value::UnionConstructor(l.clone(), kts.clone())
+            ValueF::UnionLit(l, v, kts) => rc(ExprF::App(
+                ValueF::UnionConstructor(l.clone(), kts.clone())
                     .normalize_to_expr_maybe_alpha(alpha),
                 v.normalize_to_expr_maybe_alpha(alpha),
             )),
-            Value::TextLit(elts) => {
+            ValueF::TextLit(elts) => {
                 use InterpolatedTextContents::{Expr, Text};
                 rc(ExprF::TextLit(
                     elts.iter()
@@ -171,12 +171,12 @@ impl Value {
                         .collect(),
                 ))
             }
-            Value::Equivalence(x, y) => rc(ExprF::BinOp(
+            ValueF::Equivalence(x, y) => rc(ExprF::BinOp(
                 dhall_syntax::BinOp::Equivalence,
                 x.normalize_to_expr_maybe_alpha(alpha),
                 y.normalize_to_expr_maybe_alpha(alpha),
             )),
-            Value::PartialExpr(e) => {
+            ValueF::PartialExpr(e) => {
                 rc(e.map_ref(|v| v.normalize_to_expr_maybe_alpha(alpha)))
             }
         }
@@ -184,60 +184,60 @@ impl Value {
 
     pub(crate) fn normalize_mut(&mut self) {
         match self {
-            Value::Var(_)
-            | Value::Const(_)
-            | Value::BoolLit(_)
-            | Value::NaturalLit(_)
-            | Value::IntegerLit(_)
-            | Value::DoubleLit(_) => {}
+            ValueF::Var(_)
+            | ValueF::Const(_)
+            | ValueF::BoolLit(_)
+            | ValueF::NaturalLit(_)
+            | ValueF::IntegerLit(_)
+            | ValueF::DoubleLit(_) => {}
 
-            Value::EmptyOptionalLit(tth) | Value::EmptyListLit(tth) => {
+            ValueF::EmptyOptionalLit(tth) | ValueF::EmptyListLit(tth) => {
                 tth.normalize_mut();
             }
 
-            Value::NEOptionalLit(th) => {
+            ValueF::NEOptionalLit(th) => {
                 th.normalize_mut();
             }
-            Value::Lam(_, t, e) => {
+            ValueF::Lam(_, t, e) => {
                 t.normalize_mut();
                 e.normalize_mut();
             }
-            Value::Pi(_, t, e) => {
+            ValueF::Pi(_, t, e) => {
                 t.normalize_mut();
                 e.normalize_mut();
             }
-            Value::AppliedBuiltin(_, args) => {
+            ValueF::AppliedBuiltin(_, args) => {
                 for x in args.iter_mut() {
                     x.normalize_mut();
                 }
             }
-            Value::NEListLit(elts) => {
+            ValueF::NEListLit(elts) => {
                 for x in elts.iter_mut() {
                     x.normalize_mut();
                 }
             }
-            Value::RecordLit(kvs) => {
+            ValueF::RecordLit(kvs) => {
                 for x in kvs.values_mut() {
                     x.normalize_mut();
                 }
             }
-            Value::RecordType(kvs) => {
+            ValueF::RecordType(kvs) => {
                 for x in kvs.values_mut() {
                     x.normalize_mut();
                 }
             }
-            Value::UnionType(kts) | Value::UnionConstructor(_, kts) => {
+            ValueF::UnionType(kts) | ValueF::UnionConstructor(_, kts) => {
                 for x in kts.values_mut().flat_map(|opt| opt) {
                     x.normalize_mut();
                 }
             }
-            Value::UnionLit(_, v, kts) => {
+            ValueF::UnionLit(_, v, kts) => {
                 v.normalize_mut();
                 for x in kts.values_mut().flat_map(|opt| opt) {
                     x.normalize_mut();
                 }
             }
-            Value::TextLit(elts) => {
+            ValueF::TextLit(elts) => {
                 for x in elts.iter_mut() {
                     use InterpolatedTextContents::{Expr, Text};
                     match x {
@@ -246,11 +246,11 @@ impl Value {
                     }
                 }
             }
-            Value::Equivalence(x, y) => {
+            ValueF::Equivalence(x, y) => {
                 x.normalize_mut();
                 y.normalize_mut();
             }
-            Value::PartialExpr(e) => {
+            ValueF::PartialExpr(e) => {
                 // TODO: need map_mut
                 e.map_ref(|v| {
                     v.normalize_nf();
@@ -260,75 +260,75 @@ impl Value {
     }
 
     /// Apply to a value
-    pub(crate) fn app(self, val: Value) -> Value {
+    pub(crate) fn app(self, val: ValueF) -> ValueF {
         self.app_val(val)
     }
 
     /// Apply to a value
-    pub(crate) fn app_val(self, val: Value) -> Value {
+    pub(crate) fn app_val(self, val: ValueF) -> ValueF {
         self.app_thunk(val.into_thunk())
     }
 
     /// Apply to a thunk
-    pub fn app_thunk(self, th: Thunk) -> Value {
-        Thunk::from_value(self).app_thunk(th)
+    pub fn app_thunk(self, th: Thunk) -> ValueF {
+        Thunk::from_valuef(self).app_thunk(th)
     }
 
-    pub fn from_builtin(b: Builtin) -> Value {
-        Value::AppliedBuiltin(b, vec![])
+    pub fn from_builtin(b: Builtin) -> ValueF {
+        ValueF::AppliedBuiltin(b, vec![])
     }
 }
 
-impl Shift for Value {
+impl Shift for ValueF {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
-            Value::Lam(x, t, e) => Value::Lam(
+            ValueF::Lam(x, t, e) => ValueF::Lam(
                 x.clone(),
                 t.shift(delta, var)?,
                 e.shift(delta, &var.under_binder(x))?,
             ),
-            Value::AppliedBuiltin(b, args) => Value::AppliedBuiltin(
+            ValueF::AppliedBuiltin(b, args) => ValueF::AppliedBuiltin(
                 *b,
                 args.iter()
                     .map(|v| Ok(v.shift(delta, var)?))
                     .collect::<Result<_, _>>()?,
             ),
-            Value::Pi(x, t, e) => Value::Pi(
+            ValueF::Pi(x, t, e) => ValueF::Pi(
                 x.clone(),
                 t.shift(delta, var)?,
                 e.shift(delta, &var.under_binder(x))?,
             ),
-            Value::Var(v) => Value::Var(v.shift(delta, var)?),
-            Value::Const(c) => Value::Const(*c),
-            Value::BoolLit(b) => Value::BoolLit(*b),
-            Value::NaturalLit(n) => Value::NaturalLit(*n),
-            Value::IntegerLit(n) => Value::IntegerLit(*n),
-            Value::DoubleLit(n) => Value::DoubleLit(*n),
-            Value::EmptyOptionalLit(tth) => {
-                Value::EmptyOptionalLit(tth.shift(delta, var)?)
+            ValueF::Var(v) => ValueF::Var(v.shift(delta, var)?),
+            ValueF::Const(c) => ValueF::Const(*c),
+            ValueF::BoolLit(b) => ValueF::BoolLit(*b),
+            ValueF::NaturalLit(n) => ValueF::NaturalLit(*n),
+            ValueF::IntegerLit(n) => ValueF::IntegerLit(*n),
+            ValueF::DoubleLit(n) => ValueF::DoubleLit(*n),
+            ValueF::EmptyOptionalLit(tth) => {
+                ValueF::EmptyOptionalLit(tth.shift(delta, var)?)
             }
-            Value::NEOptionalLit(th) => {
-                Value::NEOptionalLit(th.shift(delta, var)?)
+            ValueF::NEOptionalLit(th) => {
+                ValueF::NEOptionalLit(th.shift(delta, var)?)
             }
-            Value::EmptyListLit(tth) => {
-                Value::EmptyListLit(tth.shift(delta, var)?)
+            ValueF::EmptyListLit(tth) => {
+                ValueF::EmptyListLit(tth.shift(delta, var)?)
             }
-            Value::NEListLit(elts) => Value::NEListLit(
+            ValueF::NEListLit(elts) => ValueF::NEListLit(
                 elts.iter()
                     .map(|v| Ok(v.shift(delta, var)?))
                     .collect::<Result<_, _>>()?,
             ),
-            Value::RecordLit(kvs) => Value::RecordLit(
+            ValueF::RecordLit(kvs) => ValueF::RecordLit(
                 kvs.iter()
                     .map(|(k, v)| Ok((k.clone(), v.shift(delta, var)?)))
                     .collect::<Result<_, _>>()?,
             ),
-            Value::RecordType(kvs) => Value::RecordType(
+            ValueF::RecordType(kvs) => ValueF::RecordType(
                 kvs.iter()
                     .map(|(k, v)| Ok((k.clone(), v.shift(delta, var)?)))
                     .collect::<Result<_, _>>()?,
             ),
-            Value::UnionType(kts) => Value::UnionType(
+            ValueF::UnionType(kts) => ValueF::UnionType(
                 kts.iter()
                     .map(|(k, v)| {
                         Ok((
@@ -340,7 +340,7 @@ impl Shift for Value {
                     })
                     .collect::<Result<_, _>>()?,
             ),
-            Value::UnionConstructor(x, kts) => Value::UnionConstructor(
+            ValueF::UnionConstructor(x, kts) => ValueF::UnionConstructor(
                 x.clone(),
                 kts.iter()
                     .map(|(k, v)| {
@@ -353,7 +353,7 @@ impl Shift for Value {
                     })
                     .collect::<Result<_, _>>()?,
             ),
-            Value::UnionLit(x, v, kts) => Value::UnionLit(
+            ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
                 x.clone(),
                 v.shift(delta, var)?,
                 kts.iter()
@@ -367,7 +367,7 @@ impl Shift for Value {
                     })
                     .collect::<Result<_, _>>()?,
             ),
-            Value::TextLit(elts) => Value::TextLit(
+            ValueF::TextLit(elts) => ValueF::TextLit(
                 elts.iter()
                     .map(|contents| {
                         use InterpolatedTextContents::{Expr, Text};
@@ -378,10 +378,10 @@ impl Shift for Value {
                     })
                     .collect::<Result<_, _>>()?,
             ),
-            Value::Equivalence(x, y) => {
-                Value::Equivalence(x.shift(delta, var)?, y.shift(delta, var)?)
+            ValueF::Equivalence(x, y) => {
+                ValueF::Equivalence(x.shift(delta, var)?, y.shift(delta, var)?)
             }
-            Value::PartialExpr(e) => Value::PartialExpr(
+            ValueF::PartialExpr(e) => ValueF::PartialExpr(
                 e.traverse_ref_with_special_handling_of_binders(
                     |v| Ok(v.shift(delta, var)?),
                     |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
@@ -391,16 +391,16 @@ impl Shift for Value {
     }
 }
 
-impl Subst<Typed> for Value {
+impl Subst<Typed> for ValueF {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
             // Retry normalizing since substituting may allow progress
-            Value::AppliedBuiltin(b, args) => apply_builtin(
+            ValueF::AppliedBuiltin(b, args) => apply_builtin(
                 *b,
                 args.iter().map(|v| v.subst_shift(var, val)).collect(),
             ),
             // Retry normalizing since substituting may allow progress
-            Value::PartialExpr(e) => {
+            ValueF::PartialExpr(e) => {
                 normalize_one_layer(e.map_ref_with_special_handling_of_binders(
                     |v| v.subst_shift(var, val),
                     |x, v| {
@@ -412,8 +412,8 @@ impl Subst<Typed> for Value {
                 ))
             }
             // Retry normalizing since substituting may allow progress
-            Value::TextLit(elts) => {
-                Value::TextLit(squash_textlit(elts.iter().map(|contents| {
+            ValueF::TextLit(elts) => {
+                ValueF::TextLit(squash_textlit(elts.iter().map(|contents| {
                     use InterpolatedTextContents::{Expr, Text};
                     match contents {
                         Expr(th) => Expr(th.subst_shift(var, val)),
@@ -421,53 +421,53 @@ impl Subst<Typed> for Value {
                     }
                 })))
             }
-            Value::Lam(x, t, e) => Value::Lam(
+            ValueF::Lam(x, t, e) => ValueF::Lam(
                 x.clone(),
                 t.subst_shift(var, val),
                 e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
             ),
-            Value::Pi(x, t, e) => Value::Pi(
+            ValueF::Pi(x, t, e) => ValueF::Pi(
                 x.clone(),
                 t.subst_shift(var, val),
                 e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
             ),
-            Value::Var(v) if v == var => val.to_value(),
-            Value::Var(v) => Value::Var(v.shift(-1, var).unwrap()),
-            Value::Const(c) => Value::Const(*c),
-            Value::BoolLit(b) => Value::BoolLit(*b),
-            Value::NaturalLit(n) => Value::NaturalLit(*n),
-            Value::IntegerLit(n) => Value::IntegerLit(*n),
-            Value::DoubleLit(n) => Value::DoubleLit(*n),
-            Value::EmptyOptionalLit(tth) => {
-                Value::EmptyOptionalLit(tth.subst_shift(var, val))
+            ValueF::Var(v) if v == var => val.to_valuef(),
+            ValueF::Var(v) => ValueF::Var(v.shift(-1, var).unwrap()),
+            ValueF::Const(c) => ValueF::Const(*c),
+            ValueF::BoolLit(b) => ValueF::BoolLit(*b),
+            ValueF::NaturalLit(n) => ValueF::NaturalLit(*n),
+            ValueF::IntegerLit(n) => ValueF::IntegerLit(*n),
+            ValueF::DoubleLit(n) => ValueF::DoubleLit(*n),
+            ValueF::EmptyOptionalLit(tth) => {
+                ValueF::EmptyOptionalLit(tth.subst_shift(var, val))
             }
-            Value::NEOptionalLit(th) => {
-                Value::NEOptionalLit(th.subst_shift(var, val))
+            ValueF::NEOptionalLit(th) => {
+                ValueF::NEOptionalLit(th.subst_shift(var, val))
             }
-            Value::EmptyListLit(tth) => {
-                Value::EmptyListLit(tth.subst_shift(var, val))
+            ValueF::EmptyListLit(tth) => {
+                ValueF::EmptyListLit(tth.subst_shift(var, val))
             }
-            Value::NEListLit(elts) => Value::NEListLit(
+            ValueF::NEListLit(elts) => ValueF::NEListLit(
                 elts.iter().map(|v| v.subst_shift(var, val)).collect(),
             ),
-            Value::RecordLit(kvs) => Value::RecordLit(
+            ValueF::RecordLit(kvs) => ValueF::RecordLit(
                 kvs.iter()
                     .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
                     .collect(),
             ),
-            Value::RecordType(kvs) => Value::RecordType(
+            ValueF::RecordType(kvs) => ValueF::RecordType(
                 kvs.iter()
                     .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
                     .collect(),
             ),
-            Value::UnionType(kts) => Value::UnionType(
+            ValueF::UnionType(kts) => ValueF::UnionType(
                 kts.iter()
                     .map(|(k, v)| {
                         (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
                     })
                     .collect(),
             ),
-            Value::UnionConstructor(x, kts) => Value::UnionConstructor(
+            ValueF::UnionConstructor(x, kts) => ValueF::UnionConstructor(
                 x.clone(),
                 kts.iter()
                     .map(|(k, v)| {
@@ -475,7 +475,7 @@ impl Subst<Typed> for Value {
                     })
                     .collect(),
             ),
-            Value::UnionLit(x, v, kts) => Value::UnionLit(
+            ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
                 x.clone(),
                 v.subst_shift(var, val),
                 kts.iter()
@@ -484,7 +484,7 @@ impl Subst<Typed> for Value {
                     })
                     .collect(),
             ),
-            Value::Equivalence(x, y) => Value::Equivalence(
+            ValueF::Equivalence(x, y) => ValueF::Equivalence(
                 x.subst_shift(var, val),
                 y.subst_shift(var, val),
             ),
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index becd653..296e968 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -12,7 +12,7 @@ pub struct AlphaVar {
 }
 
 // Exactly like a Label, but equality returns always true.
-// This is so that Value equality is exactly alpha-equivalence.
+// This is so that ValueF equality is exactly alpha-equivalence.
 #[derive(Clone, Eq)]
 pub struct AlphaLabel(Label);
 
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index adf749c..7e74f95 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -5,7 +5,7 @@ use std::path::Path;
 use dhall_syntax::{Const, SubExpr};
 
 use crate::core::thunk::{Thunk, TypedThunk};
-use crate::core::value::Value;
+use crate::core::value::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{EncodeError, Error, ImportError, TypeError};
 
@@ -101,8 +101,8 @@ impl Typed {
     pub(crate) fn from_const(c: Const) -> Self {
         Typed(TypedThunk::from_const(c))
     }
-    pub fn from_value_and_type(v: Value, t: Type) -> Self {
-        Typed(TypedThunk::from_value_and_type(v, t))
+    pub fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
+        Typed(TypedThunk::from_valuef_and_type(v, t))
     }
     pub(crate) fn from_typethunk(th: TypedThunk) -> Self {
         Typed(th)
@@ -111,8 +111,8 @@ impl Typed {
         Typed::from_const(Const::Type)
     }
 
-    pub(crate) fn to_value(&self) -> Value {
-        self.0.to_value()
+    pub(crate) fn to_valuef(&self) -> ValueF {
+        self.0.to_valuef()
     }
     pub fn to_expr(&self) -> NormalizedSubExpr {
         self.0.to_expr()
@@ -229,7 +229,7 @@ impl std::hash::Hash for Normalized {
 impl Eq for Typed {}
 impl PartialEq for Typed {
     fn eq(&self, other: &Self) -> bool {
-        self.to_value() == other.to_value()
+        self.to_valuef() == other.to_valuef()
     }
 }
 
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 02b705d..da54726 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -6,7 +6,7 @@ use dhall_syntax::{
 };
 
 use crate::core::thunk::{Thunk, TypedThunk};
-use crate::core::value::Value;
+use crate::core::value::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr, Typed};
 
@@ -20,11 +20,11 @@ macro_rules! make_closure {
             Label::from(stringify!($var)).into(),
             $n
         );
-        Value::Var(var).into_thunk()
+        ValueF::Var(var).into_thunk()
     }};
     // Warning: assumes that $ty, as a dhall value, has type `Type`
     (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
-        Value::Lam(
+        ValueF::Lam(
             Label::from(stringify!($var)).into(),
             TypedThunk::from_thunk_simple_type(
                 make_closure!($($ty)*),
@@ -32,35 +32,35 @@ macro_rules! make_closure {
             make_closure!($($rest)*),
         ).into_thunk()
     };
-    (Natural) => { Value::from_builtin(Builtin::Natural).into_thunk() };
+    (Natural) => { ValueF::from_builtin(Builtin::Natural).into_thunk() };
     (List $($rest:tt)*) => {
-        Value::from_builtin(Builtin::List)
+        ValueF::from_builtin(Builtin::List)
             .app_thunk(make_closure!($($rest)*))
             .into_thunk()
     };
     (Some $($rest:tt)*) => {
-        Value::NEOptionalLit(make_closure!($($rest)*)).into_thunk()
+        ValueF::NEOptionalLit(make_closure!($($rest)*)).into_thunk()
     };
     (1 + $($rest:tt)*) => {
-        Value::PartialExpr(ExprF::BinOp(
+        ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::NaturalPlus,
             make_closure!($($rest)*),
-            Thunk::from_value(Value::NaturalLit(1)),
+            Thunk::from_valuef(ValueF::NaturalLit(1)),
         )).into_thunk()
     };
     ([ $($head:tt)* ] # $($tail:tt)*) => {
-        Value::PartialExpr(ExprF::BinOp(
+        ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::ListAppend,
-            Value::NEListLit(vec![make_closure!($($head)*)]).into_thunk(),
+            ValueF::NEListLit(vec![make_closure!($($head)*)]).into_thunk(),
             make_closure!($($tail)*),
         )).into_thunk()
     };
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
+pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
     use dhall_syntax::Builtin::*;
-    use Value::*;
+    use ValueF::*;
 
     // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
     let ret = match (b, args.as_slice()) {
@@ -68,23 +68,23 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             r,
             EmptyOptionalLit(TypedThunk::from_thunk_simple_type(t.clone())),
         )),
-        (NaturalIsZero, [n, r..]) => match &*n.as_value() {
+        (NaturalIsZero, [n, r..]) => match &*n.as_valuef() {
             NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
             _ => Err(()),
         },
-        (NaturalEven, [n, r..]) => match &*n.as_value() {
+        (NaturalEven, [n, r..]) => match &*n.as_valuef() {
             NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0))),
             _ => Err(()),
         },
-        (NaturalOdd, [n, r..]) => match &*n.as_value() {
+        (NaturalOdd, [n, r..]) => match &*n.as_valuef() {
             NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0))),
             _ => Err(()),
         },
-        (NaturalToInteger, [n, r..]) => match &*n.as_value() {
+        (NaturalToInteger, [n, r..]) => match &*n.as_valuef() {
             NaturalLit(n) => Ok((r, IntegerLit(*n as isize))),
             _ => Err(()),
         },
-        (NaturalShow, [n, r..]) => match &*n.as_value() {
+        (NaturalShow, [n, r..]) => match &*n.as_valuef() {
             NaturalLit(n) => Ok((
                 r,
                 TextLit(vec![InterpolatedTextContents::Text(n.to_string())]),
@@ -92,7 +92,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             _ => Err(()),
         },
         (NaturalSubtract, [a, b, r..]) => {
-            match (&*a.as_value(), &*b.as_value()) {
+            match (&*a.as_valuef(), &*b.as_valuef()) {
                 (NaturalLit(a), NaturalLit(b)) => {
                     Ok((r, NaturalLit(if b > a { b - a } else { 0 })))
                 }
@@ -102,7 +102,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                 _ => Err(()),
             }
         }
-        (IntegerShow, [n, r..]) => match &*n.as_value() {
+        (IntegerShow, [n, r..]) => match &*n.as_valuef() {
             IntegerLit(n) => {
                 let s = if *n < 0 {
                     n.to_string()
@@ -113,18 +113,18 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             }
             _ => Err(()),
         },
-        (IntegerToDouble, [n, r..]) => match &*n.as_value() {
+        (IntegerToDouble, [n, r..]) => match &*n.as_valuef() {
             IntegerLit(n) => Ok((r, DoubleLit(NaiveDouble::from(*n as f64)))),
             _ => Err(()),
         },
-        (DoubleShow, [n, r..]) => match &*n.as_value() {
+        (DoubleShow, [n, r..]) => match &*n.as_valuef() {
             DoubleLit(n) => Ok((
                 r,
                 TextLit(vec![InterpolatedTextContents::Text(n.to_string())]),
             )),
             _ => Err(()),
         },
-        (TextShow, [v, r..]) => match &*v.as_value() {
+        (TextShow, [v, r..]) => match &*v.as_valuef() {
             TextLit(elts) => {
                 match elts.as_slice() {
                     // Empty string literal.
@@ -158,41 +158,41 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             }
             _ => Err(()),
         },
-        (ListLength, [_, l, r..]) => match &*l.as_value() {
+        (ListLength, [_, l, r..]) => match &*l.as_valuef() {
             EmptyListLit(_) => Ok((r, NaturalLit(0))),
             NEListLit(xs) => Ok((r, NaturalLit(xs.len()))),
             _ => Err(()),
         },
-        (ListHead, [_, l, r..]) => match &*l.as_value() {
+        (ListHead, [_, l, r..]) => match &*l.as_valuef() {
             EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))),
             NEListLit(xs) => {
                 Ok((r, NEOptionalLit(xs.iter().next().unwrap().clone())))
             }
             _ => Err(()),
         },
-        (ListLast, [_, l, r..]) => match &*l.as_value() {
+        (ListLast, [_, l, r..]) => match &*l.as_valuef() {
             EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))),
             NEListLit(xs) => {
                 Ok((r, NEOptionalLit(xs.iter().rev().next().unwrap().clone())))
             }
             _ => Err(()),
         },
-        (ListReverse, [_, l, r..]) => match &*l.as_value() {
+        (ListReverse, [_, l, r..]) => match &*l.as_valuef() {
             EmptyListLit(n) => Ok((r, EmptyListLit(n.clone()))),
             NEListLit(xs) => {
                 Ok((r, NEListLit(xs.iter().rev().cloned().collect())))
             }
             _ => Err(()),
         },
-        (ListIndexed, [_, l, r..]) => match &*l.as_value() {
+        (ListIndexed, [_, l, r..]) => match &*l.as_valuef() {
             EmptyListLit(t) => {
                 let mut kts = HashMap::new();
                 kts.insert(
                     "index".into(),
-                    TypedThunk::from_value(Value::from_builtin(Natural)),
+                    TypedThunk::from_valuef(ValueF::from_builtin(Natural)),
                 );
                 kts.insert("value".into(), t.clone());
-                Ok((r, EmptyListLit(TypedThunk::from_value(RecordType(kts)))))
+                Ok((r, EmptyListLit(TypedThunk::from_valuef(RecordType(kts)))))
             }
             NEListLit(xs) => {
                 let xs = xs
@@ -201,20 +201,20 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                     .map(|(i, e)| {
                         let i = NaturalLit(i);
                         let mut kvs = HashMap::new();
-                        kvs.insert("index".into(), Thunk::from_value(i));
+                        kvs.insert("index".into(), Thunk::from_valuef(i));
                         kvs.insert("value".into(), e.clone());
-                        Thunk::from_value(RecordLit(kvs))
+                        Thunk::from_valuef(RecordLit(kvs))
                     })
                     .collect();
                 Ok((r, NEListLit(xs)))
             }
             _ => Err(()),
         },
-        (ListBuild, [t, f, r..]) => match &*f.as_value() {
+        (ListBuild, [t, f, r..]) => match &*f.as_valuef() {
             // fold/build fusion
-            Value::AppliedBuiltin(ListFold, args) => {
+            ValueF::AppliedBuiltin(ListFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].to_value()))
+                    Ok((r, args[1].to_valuef()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -222,7 +222,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             }
             _ => Ok((
                 r,
-                f.app_val(Value::from_builtin(List).app_thunk(t.clone()))
+                f.app_val(ValueF::from_builtin(List).app_thunk(t.clone()))
                     .app_thunk({
                         // Move `t` under new `x` variable
                         let t1 = t.under_binder(Label::from("x"));
@@ -237,8 +237,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                     ))),
             )),
         },
-        (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_value() {
-            EmptyListLit(_) => Ok((r, nil.to_value())),
+        (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_valuef() {
+            EmptyListLit(_) => Ok((r, nil.to_valuef())),
             NEListLit(xs) => {
                 let mut v = nil.clone();
                 for x in xs.iter().rev() {
@@ -248,15 +248,15 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
                         .app_thunk(v)
                         .into_thunk();
                 }
-                Ok((r, v.to_value()))
+                Ok((r, v.to_valuef()))
             }
             _ => Err(()),
         },
-        (OptionalBuild, [t, f, r..]) => match &*f.as_value() {
+        (OptionalBuild, [t, f, r..]) => match &*f.as_valuef() {
             // fold/build fusion
-            Value::AppliedBuiltin(OptionalFold, args) => {
+            ValueF::AppliedBuiltin(OptionalFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].to_value()))
+                    Ok((r, args[1].to_valuef()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -264,23 +264,25 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             }
             _ => Ok((
                 r,
-                f.app_val(Value::from_builtin(Optional).app_thunk(t.clone()))
+                f.app_val(ValueF::from_builtin(Optional).app_thunk(t.clone()))
                     .app_thunk(make_closure!(λ(x: #t) -> Some var(x, 0)))
                     .app_val(EmptyOptionalLit(
                         TypedThunk::from_thunk_simple_type(t.clone()),
                     )),
             )),
         },
-        (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_value() {
-            EmptyOptionalLit(_) => Ok((r, nothing.to_value())),
-            NEOptionalLit(x) => Ok((r, just.app_thunk(x.clone()))),
-            _ => Err(()),
-        },
-        (NaturalBuild, [f, r..]) => match &*f.as_value() {
+        (OptionalFold, [_, v, _, just, nothing, r..]) => {
+            match &*v.as_valuef() {
+                EmptyOptionalLit(_) => Ok((r, nothing.to_valuef())),
+                NEOptionalLit(x) => Ok((r, just.app_thunk(x.clone()))),
+                _ => Err(()),
+            }
+        }
+        (NaturalBuild, [f, r..]) => match &*f.as_valuef() {
             // fold/build fusion
-            Value::AppliedBuiltin(NaturalFold, args) => {
+            ValueF::AppliedBuiltin(NaturalFold, args) => {
                 if !args.is_empty() {
-                    Ok((r, args[0].to_value()))
+                    Ok((r, args[0].to_valuef()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -288,15 +290,15 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
             }
             _ => Ok((
                 r,
-                f.app_val(Value::from_builtin(Natural))
+                f.app_val(ValueF::from_builtin(Natural))
                     .app_thunk(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
                     .app_val(NaturalLit(0)),
             )),
         },
-        (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_value() {
-            NaturalLit(0) => Ok((r, zero.to_value())),
+        (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_valuef() {
+            NaturalLit(0) => Ok((r, zero.to_valuef())),
             NaturalLit(n) => {
-                let fold = Value::from_builtin(NaturalFold)
+                let fold = ValueF::from_builtin(NaturalFold)
                     .app(NaturalLit(n - 1))
                     .app_thunk(t.clone())
                     .app_thunk(succ.clone())
@@ -319,22 +321,22 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
     }
 }
 
-pub(crate) fn apply_any(f: Thunk, a: Thunk) -> Value {
-    let fallback = |f: Thunk, a: Thunk| Value::PartialExpr(ExprF::App(f, a));
+pub(crate) fn apply_any(f: Thunk, a: Thunk) -> ValueF {
+    let fallback = |f: Thunk, a: Thunk| ValueF::PartialExpr(ExprF::App(f, a));
 
-    let f_borrow = f.as_value();
+    let f_borrow = f.as_valuef();
     match &*f_borrow {
-        Value::Lam(x, _, e) => {
+        ValueF::Lam(x, _, e) => {
             let val = Typed::from_thunk_untyped(a);
-            e.subst_shift(&x.into(), &val).to_value()
+            e.subst_shift(&x.into(), &val).to_valuef()
         }
-        Value::AppliedBuiltin(b, args) => {
+        ValueF::AppliedBuiltin(b, args) => {
             use std::iter::once;
             let args = args.iter().cloned().chain(once(a.clone())).collect();
             apply_builtin(*b, args)
         }
-        Value::UnionConstructor(l, kts) => {
-            Value::UnionLit(l.clone(), a, kts.clone())
+        ValueF::UnionConstructor(l, kts) => {
+            ValueF::UnionLit(l.clone(), a, kts.clone())
         }
         _ => {
             drop(f_borrow);
@@ -358,9 +360,9 @@ pub(crate) fn squash_textlit(
             match contents {
                 Text(s) => crnt_str.push_str(&s),
                 Expr(e) => {
-                    let e_borrow = e.as_value();
+                    let e_borrow = e.as_valuef();
                     match &*e_borrow {
-                        Value::TextLit(elts2) => {
+                        ValueF::TextLit(elts2) => {
                             inner(elts2.iter().cloned(), crnt_str, ret)
                         }
                         _ => {
@@ -387,7 +389,7 @@ pub(crate) fn squash_textlit(
 
 // Small helper enum to avoid repetition
 enum Ret<'a> {
-    Value(Value),
+    ValueF(ValueF),
     Thunk(Thunk),
     ThunkRef(&'a Thunk),
     Expr(ExprF<Thunk, Normalized>),
@@ -512,67 +514,67 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         NaturalTimes, RecursiveRecordMerge, RecursiveRecordTypeMerge,
         RightBiasedRecordMerge, TextAppend,
     };
-    use Value::{
+    use ValueF::{
         BoolLit, EmptyListLit, NEListLit, NaturalLit, RecordLit, RecordType,
         TextLit,
     };
-    let x_borrow = x.as_value();
-    let y_borrow = y.as_value();
+    let x_borrow = x.as_valuef();
+    let y_borrow = y.as_valuef();
     Some(match (o, &*x_borrow, &*y_borrow) {
         (BoolAnd, BoolLit(true), _) => Ret::ThunkRef(y),
         (BoolAnd, _, BoolLit(true)) => Ret::ThunkRef(x),
-        (BoolAnd, BoolLit(false), _) => Ret::Value(BoolLit(false)),
-        (BoolAnd, _, BoolLit(false)) => Ret::Value(BoolLit(false)),
+        (BoolAnd, BoolLit(false), _) => Ret::ValueF(BoolLit(false)),
+        (BoolAnd, _, BoolLit(false)) => Ret::ValueF(BoolLit(false)),
         (BoolAnd, _, _) if x == y => Ret::ThunkRef(x),
-        (BoolOr, BoolLit(true), _) => Ret::Value(BoolLit(true)),
-        (BoolOr, _, BoolLit(true)) => Ret::Value(BoolLit(true)),
+        (BoolOr, BoolLit(true), _) => Ret::ValueF(BoolLit(true)),
+        (BoolOr, _, BoolLit(true)) => Ret::ValueF(BoolLit(true)),
         (BoolOr, BoolLit(false), _) => Ret::ThunkRef(y),
         (BoolOr, _, BoolLit(false)) => Ret::ThunkRef(x),
         (BoolOr, _, _) if x == y => Ret::ThunkRef(x),
         (BoolEQ, BoolLit(true), _) => Ret::ThunkRef(y),
         (BoolEQ, _, BoolLit(true)) => Ret::ThunkRef(x),
-        (BoolEQ, BoolLit(x), BoolLit(y)) => Ret::Value(BoolLit(x == y)),
-        (BoolEQ, _, _) if x == y => Ret::Value(BoolLit(true)),
+        (BoolEQ, BoolLit(x), BoolLit(y)) => Ret::ValueF(BoolLit(x == y)),
+        (BoolEQ, _, _) if x == y => Ret::ValueF(BoolLit(true)),
         (BoolNE, BoolLit(false), _) => Ret::ThunkRef(y),
         (BoolNE, _, BoolLit(false)) => Ret::ThunkRef(x),
-        (BoolNE, BoolLit(x), BoolLit(y)) => Ret::Value(BoolLit(x != y)),
-        (BoolNE, _, _) if x == y => Ret::Value(BoolLit(false)),
+        (BoolNE, BoolLit(x), BoolLit(y)) => Ret::ValueF(BoolLit(x != y)),
+        (BoolNE, _, _) if x == y => Ret::ValueF(BoolLit(false)),
 
         (NaturalPlus, NaturalLit(0), _) => Ret::ThunkRef(y),
         (NaturalPlus, _, NaturalLit(0)) => Ret::ThunkRef(x),
         (NaturalPlus, NaturalLit(x), NaturalLit(y)) => {
-            Ret::Value(NaturalLit(x + y))
+            Ret::ValueF(NaturalLit(x + y))
         }
-        (NaturalTimes, NaturalLit(0), _) => Ret::Value(NaturalLit(0)),
-        (NaturalTimes, _, NaturalLit(0)) => Ret::Value(NaturalLit(0)),
+        (NaturalTimes, NaturalLit(0), _) => Ret::ValueF(NaturalLit(0)),
+        (NaturalTimes, _, NaturalLit(0)) => Ret::ValueF(NaturalLit(0)),
         (NaturalTimes, NaturalLit(1), _) => Ret::ThunkRef(y),
         (NaturalTimes, _, NaturalLit(1)) => Ret::ThunkRef(x),
         (NaturalTimes, NaturalLit(x), NaturalLit(y)) => {
-            Ret::Value(NaturalLit(x * y))
+            Ret::ValueF(NaturalLit(x * y))
         }
 
         (ListAppend, EmptyListLit(_), _) => Ret::ThunkRef(y),
         (ListAppend, _, EmptyListLit(_)) => Ret::ThunkRef(x),
-        (ListAppend, NEListLit(xs), NEListLit(ys)) => {
-            Ret::Value(NEListLit(xs.iter().chain(ys.iter()).cloned().collect()))
-        }
+        (ListAppend, NEListLit(xs), NEListLit(ys)) => Ret::ValueF(NEListLit(
+            xs.iter().chain(ys.iter()).cloned().collect(),
+        )),
 
         (TextAppend, TextLit(x), _) if x.is_empty() => Ret::ThunkRef(y),
         (TextAppend, _, TextLit(y)) if y.is_empty() => Ret::ThunkRef(x),
-        (TextAppend, TextLit(x), TextLit(y)) => Ret::Value(TextLit(
+        (TextAppend, TextLit(x), TextLit(y)) => Ret::ValueF(TextLit(
             squash_textlit(x.iter().chain(y.iter()).cloned()),
         )),
         (TextAppend, TextLit(x), _) => {
             use std::iter::once;
             let y = InterpolatedTextContents::Expr(y.clone());
-            Ret::Value(TextLit(squash_textlit(
+            Ret::ValueF(TextLit(squash_textlit(
                 x.iter().cloned().chain(once(y)),
             )))
         }
         (TextAppend, _, TextLit(y)) => {
             use std::iter::once;
             let x = InterpolatedTextContents::Expr(x.clone());
-            Ret::Value(TextLit(squash_textlit(
+            Ret::ValueF(TextLit(squash_textlit(
                 once(x).chain(y.iter().cloned()),
             )))
         }
@@ -589,7 +591,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
                 // Insert only if key not already present
                 kvs.entry(x.clone()).or_insert_with(|| v.clone());
             }
-            Ret::Value(RecordLit(kvs))
+            Ret::ValueF(RecordLit(kvs))
         }
 
         (RecursiveRecordMerge, _, RecordLit(kvs)) if kvs.is_empty() => {
@@ -606,7 +608,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
                     v2.clone(),
                 ))
             });
-            Ret::Value(RecordLit(kvs))
+            Ret::ValueF(RecordLit(kvs))
         }
 
         (RecursiveRecordTypeMerge, _, RecordType(kvs)) if kvs.is_empty() => {
@@ -625,10 +627,10 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
                     ),
                 ))
             });
-            Ret::Value(RecordType(kvs))
+            Ret::ValueF(RecordType(kvs))
         }
 
-        (Equivalence, _, _) => Ret::Value(Value::Equivalence(
+        (Equivalence, _, _) => Ret::ValueF(ValueF::Equivalence(
             TypedThunk::from_thunk_simple_type(x.clone()),
             TypedThunk::from_thunk_simple_type(y.clone()),
         )),
@@ -637,8 +639,8 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
     })
 }
 
-pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
-    use Value::{
+pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
+    use ValueF::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, Lam,
         NEListLit, NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType,
         TextLit, UnionConstructor, UnionLit, UnionType,
@@ -653,9 +655,9 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
         ExprF::Annot(x, _) => Ret::Thunk(x),
         ExprF::Assert(_) => Ret::Expr(expr),
         ExprF::Lam(x, t, e) => {
-            Ret::Value(Lam(x.into(), TypedThunk::from_thunk_untyped(t), e))
+            Ret::ValueF(Lam(x.into(), TypedThunk::from_thunk_untyped(t), e))
         }
-        ExprF::Pi(x, t, e) => Ret::Value(Pi(
+        ExprF::Pi(x, t, e) => Ret::ValueF(Pi(
             x.into(),
             TypedThunk::from_thunk_untyped(t),
             TypedThunk::from_thunk_untyped(e),
@@ -664,20 +666,20 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
             let v = Typed::from_thunk_untyped(v);
             Ret::Thunk(b.subst_shift(&x.into(), &v))
         }
-        ExprF::App(v, a) => Ret::Value(v.app_thunk(a)),
-        ExprF::Builtin(b) => Ret::Value(Value::from_builtin(b)),
-        ExprF::Const(c) => Ret::Value(Value::Const(c)),
-        ExprF::BoolLit(b) => Ret::Value(BoolLit(b)),
-        ExprF::NaturalLit(n) => Ret::Value(NaturalLit(n)),
-        ExprF::IntegerLit(n) => Ret::Value(IntegerLit(n)),
-        ExprF::DoubleLit(n) => Ret::Value(DoubleLit(n)),
-        ExprF::SomeLit(e) => Ret::Value(NEOptionalLit(e)),
+        ExprF::App(v, a) => Ret::ValueF(v.app_thunk(a)),
+        ExprF::Builtin(b) => Ret::ValueF(ValueF::from_builtin(b)),
+        ExprF::Const(c) => Ret::ValueF(ValueF::Const(c)),
+        ExprF::BoolLit(b) => Ret::ValueF(BoolLit(b)),
+        ExprF::NaturalLit(n) => Ret::ValueF(NaturalLit(n)),
+        ExprF::IntegerLit(n) => Ret::ValueF(IntegerLit(n)),
+        ExprF::DoubleLit(n) => Ret::ValueF(DoubleLit(n)),
+        ExprF::SomeLit(e) => Ret::ValueF(NEOptionalLit(e)),
         ExprF::EmptyListLit(ref t) => {
             // Check if the type is of the form `List x`
-            let t_borrow = t.as_value();
+            let t_borrow = t.as_valuef();
             match &*t_borrow {
                 AppliedBuiltin(Builtin::List, args) if args.len() == 1 => {
-                    Ret::Value(EmptyListLit(
+                    Ret::ValueF(EmptyListLit(
                         TypedThunk::from_thunk_simple_type(args[0].clone()),
                     ))
                 }
@@ -688,17 +690,17 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
             }
         }
         ExprF::NEListLit(elts) => {
-            Ret::Value(NEListLit(elts.into_iter().collect()))
+            Ret::ValueF(NEListLit(elts.into_iter().collect()))
         }
         ExprF::RecordLit(kvs) => {
-            Ret::Value(RecordLit(kvs.into_iter().collect()))
+            Ret::ValueF(RecordLit(kvs.into_iter().collect()))
         }
-        ExprF::RecordType(kts) => Ret::Value(RecordType(
+        ExprF::RecordType(kts) => Ret::ValueF(RecordType(
             kts.into_iter()
                 .map(|(k, t)| (k, TypedThunk::from_thunk_untyped(t)))
                 .collect(),
         )),
-        ExprF::UnionType(kts) => Ret::Value(UnionType(
+        ExprF::UnionType(kts) => Ret::ValueF(UnionType(
             kts.into_iter()
                 .map(|(k, t)| (k, t.map(|t| TypedThunk::from_thunk_untyped(t))))
                 .collect(),
@@ -710,17 +712,17 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
             if let [Expr(th)] = elts.as_slice() {
                 Ret::Thunk(th.clone())
             } else {
-                Ret::Value(TextLit(elts))
+                Ret::ValueF(TextLit(elts))
             }
         }
         ExprF::BoolIf(ref b, ref e1, ref e2) => {
-            let b_borrow = b.as_value();
+            let b_borrow = b.as_valuef();
             match &*b_borrow {
                 BoolLit(true) => Ret::ThunkRef(e1),
                 BoolLit(false) => Ret::ThunkRef(e2),
                 _ => {
-                    let e1_borrow = e1.as_value();
-                    let e2_borrow = e2.as_value();
+                    let e1_borrow = e1.as_valuef();
+                    let e2_borrow = e2.as_valuef();
                     match (&*e1_borrow, &*e2_borrow) {
                         // Simplify `if b then True else False`
                         (BoolLit(true), BoolLit(false)) => Ret::ThunkRef(b),
@@ -741,12 +743,12 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
         },
 
         ExprF::Projection(_, ref ls) if ls.is_empty() => {
-            Ret::Value(RecordLit(HashMap::new()))
+            Ret::ValueF(RecordLit(HashMap::new()))
         }
         ExprF::Projection(ref v, ref ls) => {
-            let v_borrow = v.as_value();
+            let v_borrow = v.as_valuef();
             match &*v_borrow {
-                RecordLit(kvs) => Ret::Value(RecordLit(
+                RecordLit(kvs) => Ret::ValueF(RecordLit(
                     ls.iter()
                         .filter_map(|l| {
                             kvs.get(l).map(|x| (l.clone(), x.clone()))
@@ -760,7 +762,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
             }
         }
         ExprF::Field(ref v, ref l) => {
-            let v_borrow = v.as_value();
+            let v_borrow = v.as_valuef();
             match &*v_borrow {
                 RecordLit(kvs) => match kvs.get(l) {
                     Some(r) => Ret::Thunk(r.clone()),
@@ -770,7 +772,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
                     }
                 },
                 UnionType(kts) => {
-                    Ret::Value(UnionConstructor(l.clone(), kts.clone()))
+                    Ret::ValueF(UnionConstructor(l.clone(), kts.clone()))
                 }
                 _ => {
                     drop(v_borrow);
@@ -780,8 +782,8 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
         }
 
         ExprF::Merge(ref handlers, ref variant, _) => {
-            let handlers_borrow = handlers.as_value();
-            let variant_borrow = variant.as_value();
+            let handlers_borrow = handlers.as_valuef();
+            let variant_borrow = variant.as_valuef();
             match (&*handlers_borrow, &*variant_borrow) {
                 (RecordLit(kvs), UnionConstructor(l, _)) => match kvs.get(l) {
                     Some(h) => Ret::Thunk(h.clone()),
@@ -792,7 +794,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
                     }
                 },
                 (RecordLit(kvs), UnionLit(l, v, _)) => match kvs.get(l) {
-                    Some(h) => Ret::Value(h.app_thunk(v.clone())),
+                    Some(h) => Ret::ValueF(h.app_thunk(v.clone())),
                     None => {
                         drop(handlers_borrow);
                         drop(variant_borrow);
@@ -809,9 +811,9 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> Value {
     };
 
     match ret {
-        Ret::Value(v) => v,
-        Ret::Thunk(th) => th.to_value(),
-        Ret::ThunkRef(th) => th.to_value(),
-        Ret::Expr(expr) => Value::PartialExpr(expr),
+        Ret::ValueF(v) => v,
+        Ret::Thunk(th) => th.to_valuef(),
+        Ret::ThunkRef(th) => th.to_valuef(),
+        Ret::Expr(expr) => ValueF::PartialExpr(expr),
     }
 }
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index dd6da70..8d7a3bc 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -6,7 +6,7 @@ use dhall_syntax::{
 
 use crate::core::context::TypecheckContext;
 use crate::core::thunk::{Thunk, TypedThunk};
-use crate::core::value::Value;
+use crate::core::value::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::{Normalized, Resolved, Type, Typed};
@@ -43,7 +43,7 @@ fn tck_pi_type(
     let k = function_check(ka, kb);
 
     Ok(Typed::from_thunk_and_type(
-        Value::Pi(
+        ValueF::Pi(
             x.into(),
             TypedThunk::from_type(tx),
             TypedThunk::from_type(te),
@@ -88,7 +88,7 @@ fn tck_record_type(
     let k = k.unwrap_or(dhall_syntax::Const::Type);
 
     Ok(Typed::from_thunk_and_type(
-        Value::RecordType(new_kts).into_thunk(),
+        ValueF::RecordType(new_kts).into_thunk(),
         Type::from_const(k),
     ))
 }
@@ -132,7 +132,7 @@ fn tck_union_type(
     let k = k.unwrap_or(dhall_syntax::Const::Type);
 
     Ok(Typed::from_thunk_and_type(
-        Value::UnionType(new_kts).into_thunk(),
+        ValueF::UnionType(new_kts).into_thunk(),
         Type::from_const(k),
     ))
 }
@@ -335,14 +335,14 @@ fn type_with(
             let tx = mktype(ctx, t.clone())?;
             let ctx2 = ctx.insert_type(x, tx.clone());
             let b = type_with(&ctx2, b.clone())?;
-            let v = Value::Lam(
+            let v = ValueF::Lam(
                 x.clone().into(),
                 TypedThunk::from_type(tx.clone()),
                 b.to_thunk(),
             );
             let tb = b.get_type()?.into_owned();
             let t = tck_pi_type(ctx, x.clone(), tx, tb)?.to_type();
-            Typed::from_thunk_and_type(Thunk::from_value(v), t)
+            Typed::from_thunk_and_type(Thunk::from_valuef(v), t)
         }
         Pi(x, ta, tb) => {
             let ta = mktype(ctx, ta.clone())?;
@@ -415,8 +415,10 @@ fn type_last_layer(
         }
         App(f, a) => {
             let tf = f.get_type()?;
-            let (x, tx, tb) = match &tf.to_value() {
-                Value::Pi(x, tx, tb) => (x.clone(), tx.to_type(), tb.to_type()),
+            let (x, tx, tb) = match &tf.to_valuef() {
+                ValueF::Pi(x, tx, tb) => {
+                    (x.clone(), tx.to_type(), tb.to_type())
+                }
                 _ => return Err(mkerr(NotAFunction(f.clone()))),
             };
             if a.get_type()?.as_ref() != &tx {
@@ -437,9 +439,9 @@ fn type_last_layer(
             Ok(RetTypeOnly(x.get_type()?.into_owned()))
         }
         Assert(t) => {
-            match t.to_value() {
-                Value::Equivalence(ref x, ref y) if x == y => {}
-                Value::Equivalence(x, y) => {
+            match t.to_valuef() {
+                ValueF::Equivalence(ref x, ref y) if x == y => {}
+                ValueF::Equivalence(x, y) => {
                     return Err(mkerr(AssertMismatch(
                         x.to_typed(),
                         y.to_typed(),
@@ -470,8 +472,8 @@ fn type_last_layer(
         }
         EmptyListLit(t) => {
             let t = t.to_type();
-            match &t.to_value() {
-                Value::AppliedBuiltin(dhall_syntax::Builtin::List, args)
+            match &t.to_valuef() {
+                ValueF::AppliedBuiltin(dhall_syntax::Builtin::List, args)
                     if args.len() == 1 => {}
                 _ => {
                     return Err(TypeError::new(
@@ -504,8 +506,8 @@ fn type_last_layer(
 
             Ok(RetTypeOnly(
                 Typed::from_thunk_and_type(
-                    Value::from_builtin(dhall_syntax::Builtin::List)
-                        .app(t.to_value())
+                    ValueF::from_builtin(dhall_syntax::Builtin::List)
+                        .app(t.to_valuef())
                         .into_thunk(),
                     Typed::from_const(Type),
                 )
@@ -523,8 +525,8 @@ fn type_last_layer(
 
             Ok(RetTypeOnly(
                 Typed::from_thunk_and_type(
-                    Value::from_builtin(dhall_syntax::Builtin::Optional)
-                        .app(t.to_value())
+                    ValueF::from_builtin(dhall_syntax::Builtin::Optional)
+                        .app(t.to_valuef())
                         .into_thunk(),
                     Typed::from_const(Type).into_type(),
                 )
@@ -549,8 +551,8 @@ fn type_last_layer(
             .into_type(),
         )),
         Field(r, x) => {
-            match &r.get_type()?.to_value() {
-                Value::RecordType(kts) => match kts.get(&x) {
+            match &r.get_type()?.to_valuef() {
+                ValueF::RecordType(kts) => match kts.get(&x) {
                     Some(tth) => {
                         Ok(RetTypeOnly(tth.to_type()))
                     },
@@ -560,8 +562,8 @@ fn type_last_layer(
                 // TODO: branch here only when r.get_type() is a Const
                 _ => {
                     let r = r.to_type();
-                    match &r.to_value() {
-                        Value::UnionType(kts) => match kts.get(&x) {
+                    match &r.to_valuef() {
+                        ValueF::UnionType(kts) => match kts.get(&x) {
                             // Constructor has type T -> < x: T, ... >
                             Some(Some(t)) => {
                                 Ok(RetTypeOnly(
@@ -631,14 +633,14 @@ fn type_last_layer(
             }
 
             // Extract the LHS record type
-            let kts_x = match l_type.to_value() {
-                Value::RecordType(kts) => kts,
+            let kts_x = match l_type.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(l.clone()))),
             };
 
             // Extract the RHS record type
-            let kts_y = match r_type.to_value() {
-                Value::RecordType(kts) => kts,
+            let kts_y = match r_type.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(r.clone()))),
             };
 
@@ -672,10 +674,10 @@ fn type_last_layer(
                                inner_l: &TypedThunk,
                                inner_r: &TypedThunk|
                  -> Result<Typed, TypeError> {
-                    match (inner_l.to_value(), inner_r.to_value()) {
+                    match (inner_l.to_valuef(), inner_r.to_valuef()) {
                         (
-                            Value::RecordType(inner_l_kvs),
-                            Value::RecordType(inner_r_kvs),
+                            ValueF::RecordType(inner_l_kvs),
+                            ValueF::RecordType(inner_r_kvs),
                         ) => {
                             combine_record_types(ctx, inner_l_kvs, inner_r_kvs)
                         }
@@ -715,14 +717,14 @@ fn type_last_layer(
             }
 
             // Extract the LHS record type
-            let kts_x = match l_type.to_value() {
-                Value::RecordType(kts) => kts,
+            let kts_x = match l_type.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(l.clone()))),
             };
 
             // Extract the RHS record type
-            let kts_y = match r_type.to_value() {
-                Value::RecordType(kts) => kts,
+            let kts_y = match r_type.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(r.clone()))),
             };
 
@@ -745,10 +747,10 @@ fn type_last_layer(
                                kts_l_inner: &TypedThunk,
                                kts_r_inner: &TypedThunk|
                  -> Result<Typed, TypeError> {
-                    match (kts_l_inner.to_value(), kts_r_inner.to_value()) {
+                    match (kts_l_inner.to_valuef(), kts_r_inner.to_valuef()) {
                         (
-                            Value::RecordType(kvs_l_inner),
-                            Value::RecordType(kvs_r_inner),
+                            ValueF::RecordType(kvs_l_inner),
+                            ValueF::RecordType(kvs_r_inner),
                         ) => {
                             combine_record_types(ctx, kvs_l_inner, kvs_r_inner)
                         }
@@ -774,8 +776,8 @@ fn type_last_layer(
             };
 
             // Extract the Const of the LHS
-            let k_l = match l.get_type()?.to_value() {
-                Value::Const(k) => k,
+            let k_l = match l.get_type()?.to_valuef() {
+                ValueF::Const(k) => k,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
                         l.clone(),
@@ -784,8 +786,8 @@ fn type_last_layer(
             };
 
             // Extract the Const of the RHS
-            let k_r = match r.get_type()?.to_value() {
-                Value::Const(k) => k,
+            let k_r = match r.get_type()?.to_valuef() {
+                ValueF::Const(k) => k,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
                         r.clone(),
@@ -806,8 +808,8 @@ fn type_last_layer(
             };
 
             // Extract the LHS record type
-            let kts_x = match l.to_value() {
-                Value::RecordType(kts) => kts,
+            let kts_x = match l.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
                         l.clone(),
@@ -816,8 +818,8 @@ fn type_last_layer(
             };
 
             // Extract the RHS record type
-            let kts_y = match r.to_value() {
-                Value::RecordType(kts) => kts,
+            let kts_y = match r.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
                         r.clone(),
@@ -831,8 +833,8 @@ fn type_last_layer(
                 .and(Ok(RetTypeOnly(Typed::from_const(k))))
         }
         BinOp(o @ ListAppend, l, r) => {
-            match l.get_type()?.to_value() {
-                Value::AppliedBuiltin(List, _) => {}
+            match l.get_type()?.to_valuef() {
+                ValueF::AppliedBuiltin(List, _) => {}
                 _ => return Err(mkerr(BinOpTypeMismatch(*o, l.clone()))),
             }
 
@@ -893,13 +895,13 @@ fn type_last_layer(
             Ok(RetTypeOnly(t))
         }
         Merge(record, union, type_annot) => {
-            let handlers = match record.get_type()?.to_value() {
-                Value::RecordType(kts) => kts,
+            let handlers = match record.get_type()?.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(Merge1ArgMustBeRecord(record.clone()))),
             };
 
-            let variants = match union.get_type()?.to_value() {
-                Value::UnionType(kts) => kts,
+            let variants = match union.get_type()?.to_valuef() {
+                ValueF::UnionType(kts) => kts,
                 _ => return Err(mkerr(Merge2ArgMustBeUnion(union.clone()))),
             };
 
@@ -910,8 +912,8 @@ fn type_last_layer(
                     Some(Some(variant_type)) => {
                         let variant_type = variant_type.to_type();
                         let handler_type = handler.to_type();
-                        let (x, tx, tb) = match &handler_type.to_value() {
-                            Value::Pi(x, tx, tb) => {
+                        let (x, tx, tb) = match &handler_type.to_valuef() {
+                            ValueF::Pi(x, tx, tb) => {
                                 (x.clone(), tx.to_type(), tb.to_type())
                             }
                             _ => return Err(mkerr(NotAFunction(handler_type))),
@@ -973,8 +975,8 @@ fn type_last_layer(
         }
         Projection(record, labels) => {
             let trecord = record.get_type()?;
-            let kts = match trecord.to_value() {
-                Value::RecordType(kts) => kts,
+            let kts = match trecord.to_valuef() {
+                ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(ProjectionMustBeRecord)),
             };
 
@@ -988,7 +990,7 @@ fn type_last_layer(
 
             Ok(RetTypeOnly(
                 Typed::from_thunk_and_type(
-                    Value::RecordType(new_kts).into_thunk(),
+                    ValueF::RecordType(new_kts).into_thunk(),
                     trecord.get_type()?.into_owned(),
                 )
                 .to_type(),
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index a277977..49fd40e 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -125,7 +125,7 @@ pub use value::Value;
 // A Dhall value.
 pub mod value {
     use dhall::core::thunk::{Thunk, TypedThunk};
-    use dhall::core::value::Value as DhallValue;
+    use dhall::core::value::ValueF as DhallValue;
     use dhall::phase::{NormalizedSubExpr, Parsed, Type, Typed};
     use dhall_syntax::Builtin;
 
@@ -162,7 +162,7 @@ pub mod value {
 
         /// Assumes that the given value has type `Type`.
         pub(crate) fn make_simple_type(v: DhallValue) -> Self {
-            Value(Typed::from_value_and_type(v, Type::const_type()))
+            Value(Typed::from_valuef_and_type(v, Type::const_type()))
         }
         pub(crate) fn make_builtin_type(b: Builtin) -> Self {
             Self::make_simple_type(DhallValue::from_builtin(b))
-- 
cgit v1.3.1


From 9383d55718b86faf4c1734fe8fee3f99730499d4 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 20:05:23 +0200
Subject: Remove Const-optimization for now

---
 dhall/src/core/thunk.rs | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index cf7c097..db68169 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -45,11 +45,6 @@ pub enum TypedThunk {
     // Any value, along with (optionally) its type
     Untyped(Thunk),
     Typed(Thunk, Box<Type>),
-    // One of the base higher-kinded types.
-    // Used to avoid storing the same tower ot Type->Kind->Sort
-    // over and over again. Also enables having Sort as a value
-    // even though it doesn't itself have a type.
-    Const(Const),
 }
 
 impl ThunkInternal {
@@ -191,7 +186,6 @@ impl TypedThunk {
 
     pub(crate) fn normalize_nf(&self) -> ValueF {
         match self {
-            TypedThunk::Const(c) => ValueF::Const(*c),
             TypedThunk::Untyped(thunk) | TypedThunk::Typed(thunk, _) => {
                 thunk.normalize_nf().clone()
             }
@@ -219,7 +213,10 @@ impl TypedThunk {
         TypedThunk::Untyped(th)
     }
     pub(crate) fn from_const(c: Const) -> Self {
-        TypedThunk::Const(c)
+        match type_of_const(c) {
+            Ok(t) => TypedThunk::from_valuef_and_type(ValueF::Const(c), t),
+            Err(_) => TypedThunk::from_valuef(ValueF::Const(c)),
+        }
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
         TypedThunk::from_thunk_and_type(Thunk::from_valuef(v), t)
@@ -231,7 +228,6 @@ impl TypedThunk {
             TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => {
                 th.to_valuef()
             }
-            TypedThunk::Const(c) => ValueF::Const(*c),
         }
     }
     pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
@@ -243,7 +239,6 @@ impl TypedThunk {
     pub(crate) fn to_thunk(&self) -> Thunk {
         match self {
             TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.clone(),
-            TypedThunk::Const(c) => Thunk::from_valuef(ValueF::Const(*c)),
         }
     }
     pub(crate) fn to_type(&self) -> Type {
@@ -265,18 +260,16 @@ impl TypedThunk {
             TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => {
                 th.normalize_mut()
             }
-            TypedThunk::Const(_) => {}
         }
     }
 
     pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
         match self {
-            TypedThunk::Untyped(_) => Err(TypeError::new(
+            TypedThunk::Untyped(th) => Err(TypeError::new(
                 &TypecheckContext::new(),
                 TypeMessage::Untyped,
             )),
             TypedThunk::Typed(_, t) => Ok(Cow::Borrowed(t)),
-            TypedThunk::Const(c) => Ok(Cow::Owned(type_of_const(*c)?)),
         }
     }
 }
@@ -313,7 +306,6 @@ impl Shift for TypedThunk {
                 th.shift(delta, var)?,
                 Box::new(t.shift(delta, var)?),
             ),
-            TypedThunk::Const(c) => TypedThunk::Const(*c),
         })
     }
 }
@@ -356,7 +348,6 @@ impl Subst<Typed> for TypedThunk {
                 th.subst_shift(var, val),
                 Box::new(t.subst_shift(var, val)),
             ),
-            TypedThunk::Const(c) => TypedThunk::Const(*c),
         }
     }
 }
-- 
cgit v1.3.1


From 961dbc0e9d52691de590568c01a22d28c04fe2f5 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 21:59:11 +0200
Subject: Store type in Thunk

---
 dhall/src/core/thunk.rs | 94 +++++++++++++++++++++----------------------------
 dhall/src/core/var.rs   | 35 +++++++++++++++---
 2 files changed, 71 insertions(+), 58 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index db68169..e315a90 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -33,23 +33,18 @@ enum ThunkInternal {
 }
 
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
-/// sharing computation automatically.
-/// Uses a RefCell to share computation.
+/// sharing computation automatically. Uses a RefCell to share computation.
+/// Can optionally store a Type from the typechecking phase to preserve type information through
+/// the normalization phase.
 #[derive(Clone)]
-pub struct Thunk(Rc<RefCell<ThunkInternal>>);
+pub struct Thunk(Rc<RefCell<ThunkInternal>>, Option<Box<Type>>);
 
-/// A thunk in type position. Can optionally store a Type from the typechecking phase to preserve
-/// type information through the normalization phase.
 #[derive(Debug, Clone)]
-pub enum TypedThunk {
-    // Any value, along with (optionally) its type
-    Untyped(Thunk),
-    Typed(Thunk, Box<Type>),
-}
+pub struct TypedThunk(Thunk);
 
 impl ThunkInternal {
-    fn into_thunk(self) -> Thunk {
-        Thunk(Rc::new(RefCell::new(self)))
+    fn into_thunk(self, t: Option<Box<Type>>) -> Thunk {
+        Thunk(Rc::new(RefCell::new(self)), t)
     }
 
     fn normalize_whnf(&mut self) {
@@ -99,11 +94,16 @@ impl ThunkInternal {
 
 impl Thunk {
     pub(crate) fn from_valuef(v: ValueF) -> Thunk {
-        ThunkInternal::ValueF(WHNF, v).into_thunk()
+        ThunkInternal::ValueF(WHNF, v).into_thunk(None)
+    }
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Thunk {
+        ThunkInternal::ValueF(WHNF, v).into_thunk(Some(Box::new(t)))
     }
-
     pub(crate) fn from_partial_expr(e: ExprF<Thunk, Normalized>) -> Thunk {
-        ThunkInternal::PartialExpr(e).into_thunk()
+        ThunkInternal::PartialExpr(e).into_thunk(None)
+    }
+    pub(crate) fn with_type(self, t: Type) -> Thunk {
+        Thunk(self.0, Some(Box::new(t)))
     }
 
     // Normalizes contents to normal form; faster than `normalize_nf` if
@@ -186,9 +186,7 @@ impl TypedThunk {
 
     pub(crate) fn normalize_nf(&self) -> ValueF {
         match self {
-            TypedThunk::Untyped(thunk) | TypedThunk::Typed(thunk, _) => {
-                thunk.normalize_nf().clone()
-            }
+            TypedThunk(thunk) => thunk.normalize_nf().clone(),
         }
     }
 
@@ -204,13 +202,13 @@ impl TypedThunk {
     }
 
     pub(crate) fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
-        TypedThunk::Typed(th, Box::new(t))
+        TypedThunk(th.with_type(t))
     }
     pub fn from_thunk_simple_type(th: Thunk) -> Self {
         TypedThunk::from_thunk_and_type(th, Type::const_type())
     }
     pub(crate) fn from_thunk_untyped(th: Thunk) -> Self {
-        TypedThunk::Untyped(th)
+        TypedThunk(th)
     }
     pub(crate) fn from_const(c: Const) -> Self {
         match type_of_const(c) {
@@ -219,16 +217,14 @@ impl TypedThunk {
         }
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
-        TypedThunk::from_thunk_and_type(Thunk::from_valuef(v), t)
+        TypedThunk::from_thunk_and_type(
+            Thunk::from_valuef_and_type(v, t.clone()),
+            t,
+        )
     }
 
-    // TODO: Avoid cloning if possible
     pub(crate) fn to_valuef(&self) -> ValueF {
-        match self {
-            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => {
-                th.to_valuef()
-            }
-        }
+        self.0.to_valuef()
     }
     pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
         self.to_valuef().normalize_to_expr()
@@ -237,9 +233,7 @@ impl TypedThunk {
         self.to_valuef().normalize_to_expr_maybe_alpha(true)
     }
     pub(crate) fn to_thunk(&self) -> Thunk {
-        match self {
-            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => th.clone(),
-        }
+        self.0.clone()
     }
     pub(crate) fn to_type(&self) -> Type {
         self.clone().into_typed().into_type()
@@ -256,27 +250,28 @@ impl TypedThunk {
     }
 
     pub(crate) fn normalize_mut(&mut self) {
-        match self {
-            TypedThunk::Untyped(th) | TypedThunk::Typed(th, _) => {
-                th.normalize_mut()
-            }
-        }
+        self.0.normalize_mut()
     }
 
     pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
-        match self {
-            TypedThunk::Untyped(th) => Err(TypeError::new(
+        match &(self.0).1 {
+            Some(t) => Ok(Cow::Borrowed(&*t)),
+            None => Err(TypeError::new(
                 &TypecheckContext::new(),
                 TypeMessage::Untyped,
             )),
-            TypedThunk::Typed(_, t) => Ok(Cow::Borrowed(t)),
         }
     }
 }
 
 impl Shift for Thunk {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(self.0.borrow().shift(delta, var)?.into_thunk())
+        Some(
+            self.0
+                .borrow()
+                .shift(delta, var)?
+                .into_thunk(self.1.shift(delta, var)?),
+        )
     }
 }
 
@@ -299,20 +294,17 @@ impl Shift for ThunkInternal {
 impl Shift for TypedThunk {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
-            TypedThunk::Untyped(th) => {
-                TypedThunk::Untyped(th.shift(delta, var)?)
-            }
-            TypedThunk::Typed(th, t) => TypedThunk::Typed(
-                th.shift(delta, var)?,
-                Box::new(t.shift(delta, var)?),
-            ),
+            TypedThunk(th) => TypedThunk(th.shift(delta, var)?),
         })
     }
 }
 
 impl Subst<Typed> for Thunk {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        self.0.borrow().subst_shift(var, val).into_thunk()
+        self.0
+            .borrow()
+            .subst_shift(var, val)
+            .into_thunk(self.1.subst_shift(var, val))
     }
 }
 
@@ -341,13 +333,7 @@ impl Subst<Typed> for ThunkInternal {
 impl Subst<Typed> for TypedThunk {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
-            TypedThunk::Untyped(th) => {
-                TypedThunk::Untyped(th.subst_shift(var, val))
-            }
-            TypedThunk::Typed(th, t) => TypedThunk::Typed(
-                th.subst_shift(var, val),
-                Box::new(t.subst_shift(var, val)),
-            ),
+            TypedThunk(th) => TypedThunk(th.subst_shift(var, val)),
         }
     }
 }
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index 296e968..3af12ec 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -50,8 +50,8 @@ pub(crate) trait Shift: Sized {
     }
 }
 
-pub(crate) trait Subst<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &T) -> Self;
+pub(crate) trait Subst<S> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self;
 }
 
 impl AlphaVar {
@@ -98,8 +98,35 @@ impl Shift for () {
     }
 }
 
-impl<T> Subst<T> for () {
-    fn subst_shift(&self, _var: &AlphaVar, _val: &T) -> Self {}
+impl<T: Shift> Shift for Option<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(match self {
+            None => None,
+            Some(x) => Some(x.shift(delta, var)?),
+        })
+    }
+}
+
+impl<T: Shift> Shift for Box<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(Box::new(self.as_ref().shift(delta, var)?))
+    }
+}
+
+impl<S> Subst<S> for () {
+    fn subst_shift(&self, _var: &AlphaVar, _val: &S) -> Self {}
+}
+
+impl<S, T: Subst<S>> Subst<S> for Option<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        self.as_ref().map(|x| x.subst_shift(var, val))
+    }
+}
+
+impl<S, T: Subst<S>> Subst<S> for Box<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        Box::new(self.as_ref().subst_shift(var, val))
+    }
 }
 
 /// Equality up to alpha-equivalence
-- 
cgit v1.3.1


From cc0c6cc420ca8019665e745797758c997cc35358 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 22:33:16 +0200
Subject: Use generic Shift/Subst impls

---
 dhall/src/core/thunk.rs |  35 +++-------
 dhall/src/core/value.rs | 168 +++++++++++-----------------------------------
 dhall/src/core/var.rs   | 175 ++++++++++++++++++++++++++++++++++++++----------
 3 files changed, 186 insertions(+), 192 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index e315a90..b6358ef 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -266,24 +266,16 @@ impl TypedThunk {
 
 impl Shift for Thunk {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(
-            self.0
-                .borrow()
-                .shift(delta, var)?
-                .into_thunk(self.1.shift(delta, var)?),
-        )
+        Some(Thunk(self.0.shift(delta, var)?, self.1.shift(delta, var)?))
     }
 }
 
 impl Shift for ThunkInternal {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
-            ThunkInternal::PartialExpr(e) => ThunkInternal::PartialExpr(
-                e.traverse_ref_with_special_handling_of_binders(
-                    |v| Ok(v.shift(delta, var)?),
-                    |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
-                )?,
-            ),
+            ThunkInternal::PartialExpr(e) => {
+                ThunkInternal::PartialExpr(e.shift(delta, var)?)
+            }
             ThunkInternal::ValueF(m, v) => {
                 ThunkInternal::ValueF(*m, v.shift(delta, var)?)
             }
@@ -301,27 +293,16 @@ impl Shift for TypedThunk {
 
 impl Subst<Typed> for Thunk {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        self.0
-            .borrow()
-            .subst_shift(var, val)
-            .into_thunk(self.1.subst_shift(var, val))
+        Thunk(self.0.subst_shift(var, val), self.1.subst_shift(var, val))
     }
 }
 
 impl Subst<Typed> for ThunkInternal {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
-            ThunkInternal::PartialExpr(e) => ThunkInternal::PartialExpr(
-                e.map_ref_with_special_handling_of_binders(
-                    |v| v.subst_shift(var, val),
-                    |x, v| {
-                        v.subst_shift(
-                            &var.under_binder(x),
-                            &val.under_binder(x),
-                        )
-                    },
-                ),
-            ),
+            ThunkInternal::PartialExpr(e) => {
+                ThunkInternal::PartialExpr(e.subst_shift(var, val))
+            }
             ThunkInternal::ValueF(_, v) => {
                 // The resulting value may not stay in normal form after substitution
                 ThunkInternal::ValueF(WHNF, v.subst_shift(var, val))
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 0f2ef00..da70118 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -287,12 +287,9 @@ impl Shift for ValueF {
                 t.shift(delta, var)?,
                 e.shift(delta, &var.under_binder(x))?,
             ),
-            ValueF::AppliedBuiltin(b, args) => ValueF::AppliedBuiltin(
-                *b,
-                args.iter()
-                    .map(|v| Ok(v.shift(delta, var)?))
-                    .collect::<Result<_, _>>()?,
-            ),
+            ValueF::AppliedBuiltin(b, args) => {
+                ValueF::AppliedBuiltin(*b, args.shift(delta, var)?)
+            }
             ValueF::Pi(x, t, e) => ValueF::Pi(
                 x.clone(),
                 t.shift(delta, var)?,
@@ -313,80 +310,27 @@ impl Shift for ValueF {
             ValueF::EmptyListLit(tth) => {
                 ValueF::EmptyListLit(tth.shift(delta, var)?)
             }
-            ValueF::NEListLit(elts) => ValueF::NEListLit(
-                elts.iter()
-                    .map(|v| Ok(v.shift(delta, var)?))
-                    .collect::<Result<_, _>>()?,
-            ),
-            ValueF::RecordLit(kvs) => ValueF::RecordLit(
-                kvs.iter()
-                    .map(|(k, v)| Ok((k.clone(), v.shift(delta, var)?)))
-                    .collect::<Result<_, _>>()?,
-            ),
-            ValueF::RecordType(kvs) => ValueF::RecordType(
-                kvs.iter()
-                    .map(|(k, v)| Ok((k.clone(), v.shift(delta, var)?)))
-                    .collect::<Result<_, _>>()?,
-            ),
-            ValueF::UnionType(kts) => ValueF::UnionType(
-                kts.iter()
-                    .map(|(k, v)| {
-                        Ok((
-                            k.clone(),
-                            v.as_ref()
-                                .map(|v| Ok(v.shift(delta, var)?))
-                                .transpose()?,
-                        ))
-                    })
-                    .collect::<Result<_, _>>()?,
-            ),
-            ValueF::UnionConstructor(x, kts) => ValueF::UnionConstructor(
-                x.clone(),
-                kts.iter()
-                    .map(|(k, v)| {
-                        Ok((
-                            k.clone(),
-                            v.as_ref()
-                                .map(|v| Ok(v.shift(delta, var)?))
-                                .transpose()?,
-                        ))
-                    })
-                    .collect::<Result<_, _>>()?,
-            ),
+            ValueF::NEListLit(elts) => {
+                ValueF::NEListLit(elts.shift(delta, var)?)
+            }
+            ValueF::RecordLit(kvs) => ValueF::RecordLit(kvs.shift(delta, var)?),
+            ValueF::RecordType(kvs) => {
+                ValueF::RecordType(kvs.shift(delta, var)?)
+            }
+            ValueF::UnionType(kts) => ValueF::UnionType(kts.shift(delta, var)?),
+            ValueF::UnionConstructor(x, kts) => {
+                ValueF::UnionConstructor(x.clone(), kts.shift(delta, var)?)
+            }
             ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
                 x.clone(),
                 v.shift(delta, var)?,
-                kts.iter()
-                    .map(|(k, v)| {
-                        Ok((
-                            k.clone(),
-                            v.as_ref()
-                                .map(|v| Ok(v.shift(delta, var)?))
-                                .transpose()?,
-                        ))
-                    })
-                    .collect::<Result<_, _>>()?,
-            ),
-            ValueF::TextLit(elts) => ValueF::TextLit(
-                elts.iter()
-                    .map(|contents| {
-                        use InterpolatedTextContents::{Expr, Text};
-                        Ok(match contents {
-                            Expr(th) => Expr(th.shift(delta, var)?),
-                            Text(s) => Text(s.clone()),
-                        })
-                    })
-                    .collect::<Result<_, _>>()?,
+                kts.shift(delta, var)?,
             ),
+            ValueF::TextLit(elts) => ValueF::TextLit(elts.shift(delta, var)?),
             ValueF::Equivalence(x, y) => {
                 ValueF::Equivalence(x.shift(delta, var)?, y.shift(delta, var)?)
             }
-            ValueF::PartialExpr(e) => ValueF::PartialExpr(
-                e.traverse_ref_with_special_handling_of_binders(
-                    |v| Ok(v.shift(delta, var)?),
-                    |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
-                )?,
-            ),
+            ValueF::PartialExpr(e) => ValueF::PartialExpr(e.shift(delta, var)?),
         })
     }
 }
@@ -395,32 +339,17 @@ impl Subst<Typed> for ValueF {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
             // Retry normalizing since substituting may allow progress
-            ValueF::AppliedBuiltin(b, args) => apply_builtin(
-                *b,
-                args.iter().map(|v| v.subst_shift(var, val)).collect(),
-            ),
+            ValueF::AppliedBuiltin(b, args) => {
+                apply_builtin(*b, args.subst_shift(var, val))
+            }
             // Retry normalizing since substituting may allow progress
             ValueF::PartialExpr(e) => {
-                normalize_one_layer(e.map_ref_with_special_handling_of_binders(
-                    |v| v.subst_shift(var, val),
-                    |x, v| {
-                        v.subst_shift(
-                            &var.under_binder(x),
-                            &val.under_binder(x),
-                        )
-                    },
-                ))
+                normalize_one_layer(e.subst_shift(var, val))
             }
             // Retry normalizing since substituting may allow progress
-            ValueF::TextLit(elts) => {
-                ValueF::TextLit(squash_textlit(elts.iter().map(|contents| {
-                    use InterpolatedTextContents::{Expr, Text};
-                    match contents {
-                        Expr(th) => Expr(th.subst_shift(var, val)),
-                        Text(s) => Text(s.clone()),
-                    }
-                })))
-            }
+            ValueF::TextLit(elts) => ValueF::TextLit(squash_textlit(
+                elts.iter().map(|contents| contents.subst_shift(var, val)),
+            )),
             ValueF::Lam(x, t, e) => ValueF::Lam(
                 x.clone(),
                 t.subst_shift(var, val),
@@ -447,42 +376,25 @@ impl Subst<Typed> for ValueF {
             ValueF::EmptyListLit(tth) => {
                 ValueF::EmptyListLit(tth.subst_shift(var, val))
             }
-            ValueF::NEListLit(elts) => ValueF::NEListLit(
-                elts.iter().map(|v| v.subst_shift(var, val)).collect(),
-            ),
-            ValueF::RecordLit(kvs) => ValueF::RecordLit(
-                kvs.iter()
-                    .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
-                    .collect(),
-            ),
-            ValueF::RecordType(kvs) => ValueF::RecordType(
-                kvs.iter()
-                    .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
-                    .collect(),
-            ),
-            ValueF::UnionType(kts) => ValueF::UnionType(
-                kts.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
-                    })
-                    .collect(),
-            ),
-            ValueF::UnionConstructor(x, kts) => ValueF::UnionConstructor(
-                x.clone(),
-                kts.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
-                    })
-                    .collect(),
-            ),
+            ValueF::NEListLit(elts) => {
+                ValueF::NEListLit(elts.subst_shift(var, val))
+            }
+            ValueF::RecordLit(kvs) => {
+                ValueF::RecordLit(kvs.subst_shift(var, val))
+            }
+            ValueF::RecordType(kvs) => {
+                ValueF::RecordType(kvs.subst_shift(var, val))
+            }
+            ValueF::UnionType(kts) => {
+                ValueF::UnionType(kts.subst_shift(var, val))
+            }
+            ValueF::UnionConstructor(x, kts) => {
+                ValueF::UnionConstructor(x.clone(), kts.subst_shift(var, val))
+            }
             ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
                 x.clone(),
                 v.subst_shift(var, val),
-                kts.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
-                    })
-                    .collect(),
+                kts.subst_shift(var, val),
             ),
             ValueF::Equivalence(x, y) => ValueF::Equivalence(
                 x.subst_shift(var, val),
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index 3af12ec..8d02171 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -92,43 +92,6 @@ impl Shift for AlphaVar {
     }
 }
 
-impl Shift for () {
-    fn shift(&self, _delta: isize, _var: &AlphaVar) -> Option<Self> {
-        Some(())
-    }
-}
-
-impl<T: Shift> Shift for Option<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(match self {
-            None => None,
-            Some(x) => Some(x.shift(delta, var)?),
-        })
-    }
-}
-
-impl<T: Shift> Shift for Box<T> {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(Box::new(self.as_ref().shift(delta, var)?))
-    }
-}
-
-impl<S> Subst<S> for () {
-    fn subst_shift(&self, _var: &AlphaVar, _val: &S) -> Self {}
-}
-
-impl<S, T: Subst<S>> Subst<S> for Option<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        self.as_ref().map(|x| x.subst_shift(var, val))
-    }
-}
-
-impl<S, T: Subst<S>> Subst<S> for Box<T> {
-    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
-        Box::new(self.as_ref().subst_shift(var, val))
-    }
-}
-
 /// Equality up to alpha-equivalence
 impl std::cmp::PartialEq for AlphaVar {
     fn eq(&self, other: &Self) -> bool {
@@ -188,3 +151,141 @@ impl From<AlphaLabel> for Label {
         x.0
     }
 }
+impl Shift for () {
+    fn shift(&self, _delta: isize, _var: &AlphaVar) -> Option<Self> {
+        Some(())
+    }
+}
+
+impl<T: Shift> Shift for Option<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(match self {
+            None => None,
+            Some(x) => Some(x.shift(delta, var)?),
+        })
+    }
+}
+
+impl<T: Shift> Shift for Box<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(Box::new(self.as_ref().shift(delta, var)?))
+    }
+}
+
+impl<T: Shift> Shift for std::rc::Rc<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(std::rc::Rc::new(self.as_ref().shift(delta, var)?))
+    }
+}
+
+impl<T: Shift> Shift for std::cell::RefCell<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(std::cell::RefCell::new(self.borrow().shift(delta, var)?))
+    }
+}
+
+impl<T: Shift, E: Clone> Shift for dhall_syntax::ExprF<T, E> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(self.traverse_ref_with_special_handling_of_binders(
+            |v| Ok(v.shift(delta, var)?),
+            |x, v| Ok(v.shift(delta, &var.under_binder(x))?),
+        )?)
+    }
+}
+
+impl<T: Shift> Shift for Vec<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(
+            self.iter()
+                .map(|v| Ok(v.shift(delta, var)?))
+                .collect::<Result<_, _>>()?,
+        )
+    }
+}
+
+impl<K, T: Shift> Shift for HashMap<K, T>
+where
+    K: Clone + std::hash::Hash + Eq,
+{
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(
+            self.iter()
+                .map(|(k, v)| Ok((k.clone(), v.shift(delta, var)?)))
+                .collect::<Result<_, _>>()?,
+        )
+    }
+}
+
+impl<T: Shift> Shift for dhall_syntax::InterpolatedTextContents<T> {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        use dhall_syntax::InterpolatedTextContents::{Expr, Text};
+        Some(match self {
+            Expr(x) => Expr(x.shift(delta, var)?),
+            Text(s) => Text(s.clone()),
+        })
+    }
+}
+
+impl<S> Subst<S> for () {
+    fn subst_shift(&self, _var: &AlphaVar, _val: &S) -> Self {}
+}
+
+impl<S, T: Subst<S>> Subst<S> for Option<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        self.as_ref().map(|x| x.subst_shift(var, val))
+    }
+}
+
+impl<S, T: Subst<S>> Subst<S> for Box<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        Box::new(self.as_ref().subst_shift(var, val))
+    }
+}
+
+impl<S, T: Subst<S>> Subst<S> for std::rc::Rc<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        std::rc::Rc::new(self.as_ref().subst_shift(var, val))
+    }
+}
+
+impl<S, T: Subst<S>> Subst<S> for std::cell::RefCell<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        std::cell::RefCell::new(self.borrow().subst_shift(var, val))
+    }
+}
+
+impl<S: Shift, T: Subst<S>, E: Clone> Subst<S> for dhall_syntax::ExprF<T, E> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        self.map_ref_with_special_handling_of_binders(
+            |v| v.subst_shift(var, val),
+            |x, v| v.subst_shift(&var.under_binder(x), &val.under_binder(x)),
+        )
+    }
+}
+
+impl<S, T: Subst<S>> Subst<S> for Vec<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        self.iter().map(|v| v.subst_shift(var, val)).collect()
+    }
+}
+
+impl<S, T: Subst<S>> Subst<S> for dhall_syntax::InterpolatedTextContents<T> {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        use dhall_syntax::InterpolatedTextContents::{Expr, Text};
+        match self {
+            Expr(x) => Expr(x.subst_shift(var, val)),
+            Text(s) => Text(s.clone()),
+        }
+    }
+}
+
+impl<S, K, T: Subst<S>> Subst<S> for HashMap<K, T>
+where
+    K: Clone + std::hash::Hash + Eq,
+{
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        self.iter()
+            .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
+            .collect()
+    }
+}
-- 
cgit v1.3.1


From 8dec798929f35df15a7bc3a6caa4f0c7954c4ffc Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Fri, 16 Aug 2019 23:17:46 +0200
Subject: Share type alongside the value in a thunk

---
 dhall/src/core/thunk.rs | 138 ++++++++++++++++++++++++++++++++++--------------
 dhall/src/core/var.rs   |  12 +++++
 2 files changed, 110 insertions(+), 40 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
index b6358ef..325a410 100644
--- a/dhall/src/core/thunk.rs
+++ b/dhall/src/core/thunk.rs
@@ -1,5 +1,5 @@
 use std::borrow::Cow;
-use std::cell::{Ref, RefCell};
+use std::cell::{Ref, RefCell, RefMut};
 use std::rc::Rc;
 
 use dhall_syntax::{Const, ExprF};
@@ -21,7 +21,7 @@ enum Marker {
 }
 use Marker::{NF, WHNF};
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 enum ThunkInternal {
     /// Partially normalized value whose subexpressions have been thunked (this is returned from
     /// typechecking). Note that this is different from `ValueF::PartialExpr` because there is no
@@ -32,19 +32,29 @@ enum ThunkInternal {
     ValueF(Marker, ValueF),
 }
 
+#[derive(Debug)]
+struct TypedThunkInternal {
+    internal: ThunkInternal,
+    typ: Option<Type>,
+}
+
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
 /// sharing computation automatically. Uses a RefCell to share computation.
 /// Can optionally store a Type from the typechecking phase to preserve type information through
 /// the normalization phase.
 #[derive(Clone)]
-pub struct Thunk(Rc<RefCell<ThunkInternal>>, Option<Box<Type>>);
+pub struct Thunk(Rc<RefCell<TypedThunkInternal>>);
 
 #[derive(Debug, Clone)]
 pub struct TypedThunk(Thunk);
 
 impl ThunkInternal {
-    fn into_thunk(self, t: Option<Box<Type>>) -> Thunk {
-        Thunk(Rc::new(RefCell::new(self)), t)
+    fn into_thunk(self, t: Option<Type>) -> Thunk {
+        TypedThunkInternal {
+            internal: self,
+            typ: t,
+        }
+        .into_thunk()
     }
 
     fn normalize_whnf(&mut self) {
@@ -92,37 +102,78 @@ impl ThunkInternal {
     }
 }
 
+impl TypedThunkInternal {
+    fn into_thunk(self) -> Thunk {
+        Thunk(Rc::new(RefCell::new(self)))
+    }
+    fn as_internal(&self) -> &ThunkInternal {
+        &self.internal
+    }
+    fn as_internal_mut(&mut self) -> &mut ThunkInternal {
+        &mut self.internal
+    }
+
+    fn get_type(&self) -> Result<Type, TypeError> {
+        match &self.typ {
+            Some(t) => Ok(t.clone()),
+            None => Err(TypeError::new(
+                &TypecheckContext::new(),
+                TypeMessage::Untyped,
+            )),
+        }
+    }
+}
+
 impl Thunk {
     pub(crate) fn from_valuef(v: ValueF) -> Thunk {
         ThunkInternal::ValueF(WHNF, v).into_thunk(None)
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Thunk {
-        ThunkInternal::ValueF(WHNF, v).into_thunk(Some(Box::new(t)))
+        ThunkInternal::ValueF(WHNF, v).into_thunk(Some(t))
     }
     pub(crate) fn from_partial_expr(e: ExprF<Thunk, Normalized>) -> Thunk {
         ThunkInternal::PartialExpr(e).into_thunk(None)
     }
     pub(crate) fn with_type(self, t: Type) -> Thunk {
-        Thunk(self.0, Some(Box::new(t)))
+        self.as_internal().clone().into_thunk(Some(t))
     }
 
-    // Normalizes contents to normal form; faster than `normalize_nf` if
-    // no one else shares this thunk
-    pub(crate) fn normalize_mut(&mut self) {
+    /// Mutates the contents. If no one else shares this thunk,
+    /// mutates directly, thus avoiding a RefCell lock.
+    fn mutate_internal(&mut self, f: impl FnOnce(&mut TypedThunkInternal)) {
         match Rc::get_mut(&mut self.0) {
             // Mutate directly if sole owner
-            Some(refcell) => RefCell::get_mut(refcell).normalize_nf(),
+            Some(refcell) => f(RefCell::get_mut(refcell)),
             // Otherwise mutate through the refcell
-            None => self.0.borrow_mut().normalize_nf(),
+            None => f(&mut self.as_tinternal_mut()),
         }
     }
 
+    /// Normalizes contents to normal form; faster than `normalize_nf` if
+    /// no one else shares this thunk
+    pub(crate) fn normalize_mut(&mut self) {
+        self.mutate_internal(|i| i.as_internal_mut().normalize_nf())
+    }
+
+    fn as_tinternal(&self) -> Ref<TypedThunkInternal> {
+        self.0.borrow()
+    }
+    fn as_tinternal_mut(&mut self) -> RefMut<TypedThunkInternal> {
+        self.0.borrow_mut()
+    }
+    fn as_internal(&self) -> Ref<ThunkInternal> {
+        Ref::map(self.as_tinternal(), TypedThunkInternal::as_internal)
+    }
+    fn as_internal_mut(&self) -> RefMut<ThunkInternal> {
+        RefMut::map(self.0.borrow_mut(), TypedThunkInternal::as_internal_mut)
+    }
+
     fn do_normalize_whnf(&self) {
-        let borrow = self.0.borrow();
+        let borrow = self.as_internal();
         match &*borrow {
             ThunkInternal::PartialExpr(_) => {
                 drop(borrow);
-                self.0.borrow_mut().normalize_whnf();
+                self.as_internal_mut().normalize_whnf();
             }
             // Already at least in WHNF
             ThunkInternal::ValueF(_, _) => {}
@@ -130,11 +181,11 @@ impl Thunk {
     }
 
     fn do_normalize_nf(&self) {
-        let borrow = self.0.borrow();
+        let borrow = self.as_internal();
         match &*borrow {
             ThunkInternal::PartialExpr(_) | ThunkInternal::ValueF(WHNF, _) => {
                 drop(borrow);
-                self.0.borrow_mut().normalize_nf();
+                self.as_internal_mut().normalize_nf();
             }
             // Already in NF
             ThunkInternal::ValueF(NF, _) => {}
@@ -145,14 +196,14 @@ impl Thunk {
     // or you could run into BorrowMut panics
     pub(crate) fn normalize_nf(&self) -> Ref<ValueF> {
         self.do_normalize_nf();
-        Ref::map(self.0.borrow(), ThunkInternal::as_nf)
+        Ref::map(self.as_internal(), ThunkInternal::as_nf)
     }
 
     // WARNING: avoid normalizing any thunk while holding on to this ref
     // or you could run into BorrowMut panics
     pub(crate) fn as_valuef(&self) -> Ref<ValueF> {
         self.do_normalize_whnf();
-        Ref::map(self.0.borrow(), ThunkInternal::as_whnf)
+        Ref::map(self.as_internal(), ThunkInternal::as_whnf)
     }
 
     pub(crate) fn to_valuef(&self) -> ValueF {
@@ -173,6 +224,10 @@ impl Thunk {
     pub(crate) fn app_thunk(&self, th: Thunk) -> ValueF {
         apply_any(self.clone(), th)
     }
+
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+        Ok(Cow::Owned(self.as_tinternal().get_type()?))
+    }
 }
 
 impl TypedThunk {
@@ -185,9 +240,7 @@ impl TypedThunk {
     }
 
     pub(crate) fn normalize_nf(&self) -> ValueF {
-        match self {
-            TypedThunk(thunk) => thunk.normalize_nf().clone(),
-        }
+        self.0.normalize_nf().clone()
     }
 
     pub(crate) fn to_typed(&self) -> Typed {
@@ -217,10 +270,7 @@ impl TypedThunk {
         }
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
-        TypedThunk::from_thunk_and_type(
-            Thunk::from_valuef_and_type(v, t.clone()),
-            t,
-        )
+        TypedThunk(Thunk::from_valuef_and_type(v, t))
     }
 
     pub(crate) fn to_valuef(&self) -> ValueF {
@@ -254,19 +304,13 @@ impl TypedThunk {
     }
 
     pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
-        match &(self.0).1 {
-            Some(t) => Ok(Cow::Borrowed(&*t)),
-            None => Err(TypeError::new(
-                &TypecheckContext::new(),
-                TypeMessage::Untyped,
-            )),
-        }
+        self.0.get_type()
     }
 }
 
 impl Shift for Thunk {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(Thunk(self.0.shift(delta, var)?, self.1.shift(delta, var)?))
+        Some(Thunk(self.0.shift(delta, var)?))
     }
 }
 
@@ -285,15 +329,22 @@ impl Shift for ThunkInternal {
 
 impl Shift for TypedThunk {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(match self {
-            TypedThunk(th) => TypedThunk(th.shift(delta, var)?),
+        Some(TypedThunk(self.0.shift(delta, var)?))
+    }
+}
+
+impl Shift for TypedThunkInternal {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(TypedThunkInternal {
+            internal: self.internal.shift(delta, var)?,
+            typ: self.typ.shift(delta, var)?,
         })
     }
 }
 
 impl Subst<Typed> for Thunk {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        Thunk(self.0.subst_shift(var, val), self.1.subst_shift(var, val))
+        Thunk(self.0.subst_shift(var, val))
     }
 }
 
@@ -311,14 +362,21 @@ impl Subst<Typed> for ThunkInternal {
     }
 }
 
-impl Subst<Typed> for TypedThunk {
+impl Subst<Typed> for TypedThunkInternal {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        match self {
-            TypedThunk(th) => TypedThunk(th.subst_shift(var, val)),
+        TypedThunkInternal {
+            internal: self.internal.subst_shift(var, val),
+            typ: self.typ.subst_shift(var, val),
         }
     }
 }
 
+impl Subst<Typed> for TypedThunk {
+    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        TypedThunk(self.0.subst_shift(var, val))
+    }
+}
+
 impl std::cmp::PartialEq for Thunk {
     fn eq(&self, other: &Self) -> bool {
         *self.as_valuef() == *other.as_valuef()
@@ -335,7 +393,7 @@ impl std::cmp::Eq for TypedThunk {}
 
 impl std::fmt::Debug for Thunk {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let b: &ThunkInternal = &self.0.borrow();
+        let b: &ThunkInternal = &self.as_internal();
         match b {
             ThunkInternal::ValueF(m, v) => {
                 f.debug_tuple(&format!("Thunk@{:?}", m)).field(v).finish()
diff --git a/dhall/src/core/var.rs b/dhall/src/core/var.rs
index 8d02171..ce4d137 100644
--- a/dhall/src/core/var.rs
+++ b/dhall/src/core/var.rs
@@ -157,6 +157,12 @@ impl Shift for () {
     }
 }
 
+impl<A: Shift, B: Shift> Shift for (A, B) {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some((self.0.shift(delta, var)?, self.1.shift(delta, var)?))
+    }
+}
+
 impl<T: Shift> Shift for Option<T> {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
@@ -230,6 +236,12 @@ impl<S> Subst<S> for () {
     fn subst_shift(&self, _var: &AlphaVar, _val: &S) -> Self {}
 }
 
+impl<S, A: Subst<S>, B: Subst<S>> Subst<S> for (A, B) {
+    fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
+        (self.0.subst_shift(var, val), self.1.subst_shift(var, val))
+    }
+}
+
 impl<S, T: Subst<S>> Subst<S> for Option<T> {
     fn subst_shift(&self, var: &AlphaVar, val: &S) -> Self {
         self.as_ref().map(|x| x.subst_shift(var, val))
-- 
cgit v1.3.1


From 6753a1f97bb674d91dd4d42f2ddb25a8119e070d Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sat, 17 Aug 2019 19:00:43 +0200
Subject: s/Thunk/Value/

---
 dhall/src/core/context.rs    |  14 +-
 dhall/src/core/mod.rs        |   2 +-
 dhall/src/core/thunk.rs      | 406 ------------------------
 dhall/src/core/value.rs      | 723 ++++++++++++++++++++++---------------------
 dhall/src/core/valuef.rs     | 405 ++++++++++++++++++++++++
 dhall/src/phase/mod.rs       |  26 +-
 dhall/src/phase/normalize.rs | 208 +++++++------
 dhall/src/phase/typecheck.rs |  68 ++--
 serde_dhall/src/lib.rs       |  17 +-
 9 files changed, 936 insertions(+), 933 deletions(-)
 delete mode 100644 dhall/src/core/thunk.rs
 create mode 100644 dhall/src/core/valuef.rs

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index b1fbde9..e1a23a9 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -3,8 +3,8 @@ use std::rc::Rc;
 
 use dhall_syntax::{Label, V};
 
-use crate::core::thunk::Thunk;
-use crate::core::value::ValueF;
+use crate::core::value::Value;
+use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::TypeError;
 use crate::phase::{Type, Typed};
@@ -12,7 +12,7 @@ use crate::phase::{Type, Typed};
 #[derive(Debug, Clone)]
 enum CtxItem {
     Kept(AlphaVar, Type),
-    Replaced(Thunk, Type),
+    Replaced(Value, Type),
 }
 
 #[derive(Debug, Clone)]
@@ -31,7 +31,7 @@ impl TypecheckContext {
         let mut vec = self.0.as_ref().clone();
         vec.push((
             x.clone(),
-            CtxItem::Replaced(e.to_thunk(), e.get_type()?.into_owned()),
+            CtxItem::Replaced(e.to_value(), e.get_type()?.into_owned()),
         ));
         Ok(TypecheckContext(Rc::new(vec)))
     }
@@ -44,11 +44,11 @@ impl TypecheckContext {
                     let i = i.under_multiple_binders(&shift_map);
                     let (th, t) = match i {
                         CtxItem::Kept(newvar, t) => {
-                            (ValueF::Var(newvar).into_thunk(), t)
+                            (ValueF::Var(newvar).into_value(), t)
                         }
                         CtxItem::Replaced(th, t) => (th, t),
                     };
-                    return Some(Typed::from_thunk_and_type(th, t));
+                    return Some(Typed::from_value_and_type(th, t));
                 }
                 Some(newvar) => var = newvar,
             };
@@ -133,7 +133,7 @@ impl Subst<Typed> for CtxItem {
             ),
             CtxItem::Kept(v, t) => match v.shift(-1, var) {
                 None => {
-                    CtxItem::Replaced(val.to_thunk(), t.subst_shift(var, val))
+                    CtxItem::Replaced(val.to_value(), t.subst_shift(var, val))
                 }
                 Some(newvar) => CtxItem::Kept(newvar, t.subst_shift(var, val)),
             },
diff --git a/dhall/src/core/mod.rs b/dhall/src/core/mod.rs
index 0667df8..08213f7 100644
--- a/dhall/src/core/mod.rs
+++ b/dhall/src/core/mod.rs
@@ -1,4 +1,4 @@
 pub mod context;
-pub mod thunk;
 pub mod value;
+pub mod valuef;
 pub mod var;
diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs
deleted file mode 100644
index 325a410..0000000
--- a/dhall/src/core/thunk.rs
+++ /dev/null
@@ -1,406 +0,0 @@
-use std::borrow::Cow;
-use std::cell::{Ref, RefCell, RefMut};
-use std::rc::Rc;
-
-use dhall_syntax::{Const, ExprF};
-
-use crate::core::context::TypecheckContext;
-use crate::core::value::ValueF;
-use crate::core::var::{AlphaVar, Shift, Subst};
-use crate::error::{TypeError, TypeMessage};
-use crate::phase::normalize::{apply_any, normalize_one_layer, OutputSubExpr};
-use crate::phase::typecheck::type_of_const;
-use crate::phase::{Normalized, NormalizedSubExpr, Type, Typed};
-
-#[derive(Debug, Clone, Copy)]
-enum Marker {
-    /// Weak Head Normal Form, i.e. subexpressions may not be normalized
-    WHNF,
-    /// Normal form, i.e. completely normalized
-    NF,
-}
-use Marker::{NF, WHNF};
-
-#[derive(Debug, Clone)]
-enum ThunkInternal {
-    /// Partially normalized value whose subexpressions have been thunked (this is returned from
-    /// typechecking). Note that this is different from `ValueF::PartialExpr` because there is no
-    /// requirement of WHNF here.
-    PartialExpr(ExprF<Thunk, Normalized>),
-    /// Partially normalized value.
-    /// Invariant: if the marker is `NF`, the value must be fully normalized
-    ValueF(Marker, ValueF),
-}
-
-#[derive(Debug)]
-struct TypedThunkInternal {
-    internal: ThunkInternal,
-    typ: Option<Type>,
-}
-
-/// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
-/// sharing computation automatically. Uses a RefCell to share computation.
-/// Can optionally store a Type from the typechecking phase to preserve type information through
-/// the normalization phase.
-#[derive(Clone)]
-pub struct Thunk(Rc<RefCell<TypedThunkInternal>>);
-
-#[derive(Debug, Clone)]
-pub struct TypedThunk(Thunk);
-
-impl ThunkInternal {
-    fn into_thunk(self, t: Option<Type>) -> Thunk {
-        TypedThunkInternal {
-            internal: self,
-            typ: t,
-        }
-        .into_thunk()
-    }
-
-    fn normalize_whnf(&mut self) {
-        match self {
-            ThunkInternal::PartialExpr(e) => {
-                *self =
-                    ThunkInternal::ValueF(WHNF, normalize_one_layer(e.clone()))
-            }
-            // Already at least in WHNF
-            ThunkInternal::ValueF(_, _) => {}
-        }
-    }
-
-    fn normalize_nf(&mut self) {
-        match self {
-            ThunkInternal::PartialExpr(_) => {
-                self.normalize_whnf();
-                self.normalize_nf();
-            }
-            ThunkInternal::ValueF(m @ WHNF, v) => {
-                v.normalize_mut();
-                *m = NF;
-            }
-            // Already in NF
-            ThunkInternal::ValueF(NF, _) => {}
-        }
-    }
-
-    // Always use normalize_whnf before
-    fn as_whnf(&self) -> &ValueF {
-        match self {
-            ThunkInternal::PartialExpr(_) => unreachable!(),
-            ThunkInternal::ValueF(_, v) => v,
-        }
-    }
-
-    // Always use normalize_nf before
-    fn as_nf(&self) -> &ValueF {
-        match self {
-            ThunkInternal::PartialExpr(_) | ThunkInternal::ValueF(WHNF, _) => {
-                unreachable!()
-            }
-            ThunkInternal::ValueF(NF, v) => v,
-        }
-    }
-}
-
-impl TypedThunkInternal {
-    fn into_thunk(self) -> Thunk {
-        Thunk(Rc::new(RefCell::new(self)))
-    }
-    fn as_internal(&self) -> &ThunkInternal {
-        &self.internal
-    }
-    fn as_internal_mut(&mut self) -> &mut ThunkInternal {
-        &mut self.internal
-    }
-
-    fn get_type(&self) -> Result<Type, TypeError> {
-        match &self.typ {
-            Some(t) => Ok(t.clone()),
-            None => Err(TypeError::new(
-                &TypecheckContext::new(),
-                TypeMessage::Untyped,
-            )),
-        }
-    }
-}
-
-impl Thunk {
-    pub(crate) fn from_valuef(v: ValueF) -> Thunk {
-        ThunkInternal::ValueF(WHNF, v).into_thunk(None)
-    }
-    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Thunk {
-        ThunkInternal::ValueF(WHNF, v).into_thunk(Some(t))
-    }
-    pub(crate) fn from_partial_expr(e: ExprF<Thunk, Normalized>) -> Thunk {
-        ThunkInternal::PartialExpr(e).into_thunk(None)
-    }
-    pub(crate) fn with_type(self, t: Type) -> Thunk {
-        self.as_internal().clone().into_thunk(Some(t))
-    }
-
-    /// Mutates the contents. If no one else shares this thunk,
-    /// mutates directly, thus avoiding a RefCell lock.
-    fn mutate_internal(&mut self, f: impl FnOnce(&mut TypedThunkInternal)) {
-        match Rc::get_mut(&mut self.0) {
-            // Mutate directly if sole owner
-            Some(refcell) => f(RefCell::get_mut(refcell)),
-            // Otherwise mutate through the refcell
-            None => f(&mut self.as_tinternal_mut()),
-        }
-    }
-
-    /// Normalizes contents to normal form; faster than `normalize_nf` if
-    /// no one else shares this thunk
-    pub(crate) fn normalize_mut(&mut self) {
-        self.mutate_internal(|i| i.as_internal_mut().normalize_nf())
-    }
-
-    fn as_tinternal(&self) -> Ref<TypedThunkInternal> {
-        self.0.borrow()
-    }
-    fn as_tinternal_mut(&mut self) -> RefMut<TypedThunkInternal> {
-        self.0.borrow_mut()
-    }
-    fn as_internal(&self) -> Ref<ThunkInternal> {
-        Ref::map(self.as_tinternal(), TypedThunkInternal::as_internal)
-    }
-    fn as_internal_mut(&self) -> RefMut<ThunkInternal> {
-        RefMut::map(self.0.borrow_mut(), TypedThunkInternal::as_internal_mut)
-    }
-
-    fn do_normalize_whnf(&self) {
-        let borrow = self.as_internal();
-        match &*borrow {
-            ThunkInternal::PartialExpr(_) => {
-                drop(borrow);
-                self.as_internal_mut().normalize_whnf();
-            }
-            // Already at least in WHNF
-            ThunkInternal::ValueF(_, _) => {}
-        }
-    }
-
-    fn do_normalize_nf(&self) {
-        let borrow = self.as_internal();
-        match &*borrow {
-            ThunkInternal::PartialExpr(_) | ThunkInternal::ValueF(WHNF, _) => {
-                drop(borrow);
-                self.as_internal_mut().normalize_nf();
-            }
-            // Already in NF
-            ThunkInternal::ValueF(NF, _) => {}
-        }
-    }
-
-    // WARNING: avoid normalizing any thunk while holding on to this ref
-    // or you could run into BorrowMut panics
-    pub(crate) fn normalize_nf(&self) -> Ref<ValueF> {
-        self.do_normalize_nf();
-        Ref::map(self.as_internal(), ThunkInternal::as_nf)
-    }
-
-    // WARNING: avoid normalizing any thunk while holding on to this ref
-    // or you could run into BorrowMut panics
-    pub(crate) fn as_valuef(&self) -> Ref<ValueF> {
-        self.do_normalize_whnf();
-        Ref::map(self.as_internal(), ThunkInternal::as_whnf)
-    }
-
-    pub(crate) fn to_valuef(&self) -> ValueF {
-        self.as_valuef().clone()
-    }
-
-    pub(crate) fn normalize_to_expr_maybe_alpha(
-        &self,
-        alpha: bool,
-    ) -> OutputSubExpr {
-        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
-    }
-
-    pub(crate) fn app_val(&self, val: ValueF) -> ValueF {
-        self.app_thunk(val.into_thunk())
-    }
-
-    pub(crate) fn app_thunk(&self, th: Thunk) -> ValueF {
-        apply_any(self.clone(), th)
-    }
-
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
-        Ok(Cow::Owned(self.as_tinternal().get_type()?))
-    }
-}
-
-impl TypedThunk {
-    pub(crate) fn from_valuef(v: ValueF) -> TypedThunk {
-        TypedThunk::from_thunk_untyped(Thunk::from_valuef(v))
-    }
-
-    pub(crate) fn from_type(t: Type) -> TypedThunk {
-        t.into_typethunk()
-    }
-
-    pub(crate) fn normalize_nf(&self) -> ValueF {
-        self.0.normalize_nf().clone()
-    }
-
-    pub(crate) fn to_typed(&self) -> Typed {
-        self.clone().into_typed()
-    }
-
-    pub(crate) fn normalize_to_expr_maybe_alpha(
-        &self,
-        alpha: bool,
-    ) -> OutputSubExpr {
-        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
-    }
-
-    pub(crate) fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
-        TypedThunk(th.with_type(t))
-    }
-    pub fn from_thunk_simple_type(th: Thunk) -> Self {
-        TypedThunk::from_thunk_and_type(th, Type::const_type())
-    }
-    pub(crate) fn from_thunk_untyped(th: Thunk) -> Self {
-        TypedThunk(th)
-    }
-    pub(crate) fn from_const(c: Const) -> Self {
-        match type_of_const(c) {
-            Ok(t) => TypedThunk::from_valuef_and_type(ValueF::Const(c), t),
-            Err(_) => TypedThunk::from_valuef(ValueF::Const(c)),
-        }
-    }
-    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
-        TypedThunk(Thunk::from_valuef_and_type(v, t))
-    }
-
-    pub(crate) fn to_valuef(&self) -> ValueF {
-        self.0.to_valuef()
-    }
-    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
-        self.to_valuef().normalize_to_expr()
-    }
-    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
-        self.to_valuef().normalize_to_expr_maybe_alpha(true)
-    }
-    pub(crate) fn to_thunk(&self) -> Thunk {
-        self.0.clone()
-    }
-    pub(crate) fn to_type(&self) -> Type {
-        self.clone().into_typed().into_type()
-    }
-    pub(crate) fn into_typed(self) -> Typed {
-        Typed::from_typethunk(self)
-    }
-    pub(crate) fn as_const(&self) -> Option<Const> {
-        // TODO: avoid clone
-        match &self.to_valuef() {
-            ValueF::Const(c) => Some(*c),
-            _ => None,
-        }
-    }
-
-    pub(crate) fn normalize_mut(&mut self) {
-        self.0.normalize_mut()
-    }
-
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
-        self.0.get_type()
-    }
-}
-
-impl Shift for Thunk {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(Thunk(self.0.shift(delta, var)?))
-    }
-}
-
-impl Shift for ThunkInternal {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(match self {
-            ThunkInternal::PartialExpr(e) => {
-                ThunkInternal::PartialExpr(e.shift(delta, var)?)
-            }
-            ThunkInternal::ValueF(m, v) => {
-                ThunkInternal::ValueF(*m, v.shift(delta, var)?)
-            }
-        })
-    }
-}
-
-impl Shift for TypedThunk {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(TypedThunk(self.0.shift(delta, var)?))
-    }
-}
-
-impl Shift for TypedThunkInternal {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(TypedThunkInternal {
-            internal: self.internal.shift(delta, var)?,
-            typ: self.typ.shift(delta, var)?,
-        })
-    }
-}
-
-impl Subst<Typed> for Thunk {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        Thunk(self.0.subst_shift(var, val))
-    }
-}
-
-impl Subst<Typed> for ThunkInternal {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        match self {
-            ThunkInternal::PartialExpr(e) => {
-                ThunkInternal::PartialExpr(e.subst_shift(var, val))
-            }
-            ThunkInternal::ValueF(_, v) => {
-                // The resulting value may not stay in normal form after substitution
-                ThunkInternal::ValueF(WHNF, v.subst_shift(var, val))
-            }
-        }
-    }
-}
-
-impl Subst<Typed> for TypedThunkInternal {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        TypedThunkInternal {
-            internal: self.internal.subst_shift(var, val),
-            typ: self.typ.subst_shift(var, val),
-        }
-    }
-}
-
-impl Subst<Typed> for TypedThunk {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        TypedThunk(self.0.subst_shift(var, val))
-    }
-}
-
-impl std::cmp::PartialEq for Thunk {
-    fn eq(&self, other: &Self) -> bool {
-        *self.as_valuef() == *other.as_valuef()
-    }
-}
-impl std::cmp::Eq for Thunk {}
-
-impl std::cmp::PartialEq for TypedThunk {
-    fn eq(&self, other: &Self) -> bool {
-        self.to_valuef() == other.to_valuef()
-    }
-}
-impl std::cmp::Eq for TypedThunk {}
-
-impl std::fmt::Debug for Thunk {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let b: &ThunkInternal = &self.as_internal();
-        match b {
-            ThunkInternal::ValueF(m, v) => {
-                f.debug_tuple(&format!("Thunk@{:?}", m)).field(v).finish()
-            }
-            ThunkInternal::PartialExpr(e) => {
-                f.debug_tuple("Thunk@PartialExpr").field(e).finish()
-            }
-        }
-    }
-}
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index da70118..5c29bf0 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -1,405 +1,406 @@
-use std::collections::HashMap;
-
-use dhall_syntax::{
-    rc, Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label,
-    NaiveDouble, Natural,
-};
-
-use crate::core::thunk::{Thunk, TypedThunk};
-use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
-use crate::phase::normalize::{
-    apply_builtin, normalize_one_layer, squash_textlit, OutputSubExpr,
-};
-use crate::phase::{Normalized, Typed};
-
-/// A semantic value. The invariants ensure this value represents a Weak-Head
-/// Normal Form (WHNF). This means that this first constructor is the first constructor of the
-/// final Normal Form (NF).
-/// This WHNF must be preserved by operations on `ValueF`s. In particular, `subst_shift` could break
-/// the invariants so need to be careful to reevaluate as needed.
-/// Subexpressions are Thunks, which are partially evaluated expressions that are normalized
-/// on-demand. When all the Thunks in a ValueF are at least in WHNF, and recursively so, then the
-/// ValueF is in NF. This is because WHNF ensures that we have the first constructor of the NF; so
-/// if we have the first constructor of the NF at all levels, we actually have the NF.
-/// Equality is up to alpha-equivalence (renaming of bound variables) and beta-equivalence
-/// (normalization). Equality will normalize only as needed.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum ValueF {
-    /// Closures
-    Lam(AlphaLabel, TypedThunk, Thunk),
-    Pi(AlphaLabel, TypedThunk, TypedThunk),
-    // Invariant: the evaluation must not be able to progress further.
-    AppliedBuiltin(Builtin, Vec<Thunk>),
-
-    Var(AlphaVar),
-    Const(Const),
-    BoolLit(bool),
-    NaturalLit(Natural),
-    IntegerLit(Integer),
-    DoubleLit(NaiveDouble),
-    EmptyOptionalLit(TypedThunk),
-    NEOptionalLit(Thunk),
-    // EmptyListLit(t) means `[] : List t`, not `[] : t`
-    EmptyListLit(TypedThunk),
-    NEListLit(Vec<Thunk>),
-    RecordLit(HashMap<Label, Thunk>),
-    RecordType(HashMap<Label, TypedThunk>),
-    UnionType(HashMap<Label, Option<TypedThunk>>),
-    UnionConstructor(Label, HashMap<Label, Option<TypedThunk>>),
-    UnionLit(Label, Thunk, HashMap<Label, Option<TypedThunk>>),
-    // Invariant: this must not contain interpolations that are themselves TextLits, and
-    // contiguous text values must be merged.
-    TextLit(Vec<InterpolatedTextContents<Thunk>>),
-    Equivalence(TypedThunk, TypedThunk),
-    // Invariant: this must not contain a value captured by one of the variants above.
-    PartialExpr(ExprF<Thunk, Normalized>),
+use std::borrow::Cow;
+use std::cell::{Ref, RefCell, RefMut};
+use std::rc::Rc;
+
+use dhall_syntax::{Const, ExprF};
+
+use crate::core::context::TypecheckContext;
+use crate::core::valuef::ValueF;
+use crate::core::var::{AlphaVar, Shift, Subst};
+use crate::error::{TypeError, TypeMessage};
+use crate::phase::normalize::{apply_any, normalize_one_layer, OutputSubExpr};
+use crate::phase::typecheck::type_of_const;
+use crate::phase::{Normalized, NormalizedSubExpr, Type, Typed};
+
+#[derive(Debug, Clone, Copy)]
+enum Marker {
+    /// Weak Head Normal Form, i.e. subexpressions may not be normalized
+    WHNF,
+    /// Normal form, i.e. completely normalized
+    NF,
 }
+use Marker::{NF, WHNF};
 
-impl ValueF {
-    pub(crate) fn into_thunk(self) -> Thunk {
-        Thunk::from_valuef(self)
-    }
+#[derive(Debug, Clone)]
+enum ValueInternal {
+    /// Partially normalized value whose subexpressions have been thunked (this is returned from
+    /// typechecking). Note that this is different from `ValueF::PartialExpr` because there is no
+    /// requirement of WHNF here.
+    PartialExpr(ExprF<Value, Normalized>),
+    /// Partially normalized value.
+    /// Invariant: if the marker is `NF`, the value must be fully normalized
+    ValueF(Marker, ValueF),
+}
 
-    /// Convert the value to a fully normalized syntactic expression
-    pub(crate) fn normalize_to_expr(&self) -> OutputSubExpr {
-        self.normalize_to_expr_maybe_alpha(false)
+#[derive(Debug)]
+struct TypedValueInternal {
+    internal: ValueInternal,
+    typ: Option<Type>,
+}
+
+/// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
+/// sharing computation automatically. Uses a RefCell to share computation.
+/// Can optionally store a Type from typechecking to preserve type information through
+/// normalization.
+#[derive(Clone)]
+pub struct Value(Rc<RefCell<TypedValueInternal>>);
+
+#[derive(Debug, Clone)]
+pub struct TypedValue(Value);
+
+impl ValueInternal {
+    fn into_value(self, t: Option<Type>) -> Value {
+        TypedValueInternal {
+            internal: self,
+            typ: t,
+        }
+        .into_value()
     }
-    /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
-    /// if alpha is `true`
-    pub(crate) fn normalize_to_expr_maybe_alpha(
-        &self,
-        alpha: bool,
-    ) -> OutputSubExpr {
+
+    fn normalize_whnf(&mut self) {
         match self {
-            ValueF::Lam(x, t, e) => rc(ExprF::Lam(
-                x.to_label_maybe_alpha(alpha),
-                t.normalize_to_expr_maybe_alpha(alpha),
-                e.normalize_to_expr_maybe_alpha(alpha),
-            )),
-            ValueF::AppliedBuiltin(b, args) => {
-                let mut e = rc(ExprF::Builtin(*b));
-                for v in args {
-                    e = rc(ExprF::App(
-                        e,
-                        v.normalize_to_expr_maybe_alpha(alpha),
-                    ));
-                }
-                e
+            ValueInternal::PartialExpr(e) => {
+                *self =
+                    ValueInternal::ValueF(WHNF, normalize_one_layer(e.clone()))
             }
-            ValueF::Pi(x, t, e) => rc(ExprF::Pi(
-                x.to_label_maybe_alpha(alpha),
-                t.normalize_to_expr_maybe_alpha(alpha),
-                e.normalize_to_expr_maybe_alpha(alpha),
-            )),
-            ValueF::Var(v) => rc(ExprF::Var(v.to_var(alpha))),
-            ValueF::Const(c) => rc(ExprF::Const(*c)),
-            ValueF::BoolLit(b) => rc(ExprF::BoolLit(*b)),
-            ValueF::NaturalLit(n) => rc(ExprF::NaturalLit(*n)),
-            ValueF::IntegerLit(n) => rc(ExprF::IntegerLit(*n)),
-            ValueF::DoubleLit(n) => rc(ExprF::DoubleLit(*n)),
-            ValueF::EmptyOptionalLit(n) => rc(ExprF::App(
-                rc(ExprF::Builtin(Builtin::OptionalNone)),
-                n.normalize_to_expr_maybe_alpha(alpha),
-            )),
-            ValueF::NEOptionalLit(n) => {
-                rc(ExprF::SomeLit(n.normalize_to_expr_maybe_alpha(alpha)))
+            // Already at least in WHNF
+            ValueInternal::ValueF(_, _) => {}
+        }
+    }
+
+    fn normalize_nf(&mut self) {
+        match self {
+            ValueInternal::PartialExpr(_) => {
+                self.normalize_whnf();
+                self.normalize_nf();
             }
-            ValueF::EmptyListLit(n) => rc(ExprF::EmptyListLit(rc(ExprF::App(
-                rc(ExprF::Builtin(Builtin::List)),
-                n.normalize_to_expr_maybe_alpha(alpha),
-            )))),
-            ValueF::NEListLit(elts) => rc(ExprF::NEListLit(
-                elts.iter()
-                    .map(|n| n.normalize_to_expr_maybe_alpha(alpha))
-                    .collect(),
-            )),
-            ValueF::RecordLit(kvs) => rc(ExprF::RecordLit(
-                kvs.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
-                    })
-                    .collect(),
-            )),
-            ValueF::RecordType(kts) => rc(ExprF::RecordType(
-                kts.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
-                    })
-                    .collect(),
-            )),
-            ValueF::UnionType(kts) => rc(ExprF::UnionType(
-                kts.iter()
-                    .map(|(k, v)| {
-                        (
-                            k.clone(),
-                            v.as_ref().map(|v| {
-                                v.normalize_to_expr_maybe_alpha(alpha)
-                            }),
-                        )
-                    })
-                    .collect(),
-            )),
-            ValueF::UnionConstructor(l, kts) => {
-                let kts = kts
-                    .iter()
-                    .map(|(k, v)| {
-                        (
-                            k.clone(),
-                            v.as_ref().map(|v| {
-                                v.normalize_to_expr_maybe_alpha(alpha)
-                            }),
-                        )
-                    })
-                    .collect();
-                rc(ExprF::Field(rc(ExprF::UnionType(kts)), l.clone()))
+            ValueInternal::ValueF(m @ WHNF, v) => {
+                v.normalize_mut();
+                *m = NF;
             }
-            ValueF::UnionLit(l, v, kts) => rc(ExprF::App(
-                ValueF::UnionConstructor(l.clone(), kts.clone())
-                    .normalize_to_expr_maybe_alpha(alpha),
-                v.normalize_to_expr_maybe_alpha(alpha),
-            )),
-            ValueF::TextLit(elts) => {
-                use InterpolatedTextContents::{Expr, Text};
-                rc(ExprF::TextLit(
-                    elts.iter()
-                        .map(|contents| match contents {
-                            Expr(e) => {
-                                Expr(e.normalize_to_expr_maybe_alpha(alpha))
-                            }
-                            Text(s) => Text(s.clone()),
-                        })
-                        .collect(),
-                ))
+            // Already in NF
+            ValueInternal::ValueF(NF, _) => {}
+        }
+    }
+
+    // Always use normalize_whnf before
+    fn as_whnf(&self) -> &ValueF {
+        match self {
+            ValueInternal::PartialExpr(_) => unreachable!(),
+            ValueInternal::ValueF(_, v) => v,
+        }
+    }
+
+    // Always use normalize_nf before
+    fn as_nf(&self) -> &ValueF {
+        match self {
+            ValueInternal::PartialExpr(_) | ValueInternal::ValueF(WHNF, _) => {
+                unreachable!()
             }
-            ValueF::Equivalence(x, y) => rc(ExprF::BinOp(
-                dhall_syntax::BinOp::Equivalence,
-                x.normalize_to_expr_maybe_alpha(alpha),
-                y.normalize_to_expr_maybe_alpha(alpha),
+            ValueInternal::ValueF(NF, v) => v,
+        }
+    }
+}
+
+impl TypedValueInternal {
+    fn into_value(self) -> Value {
+        Value(Rc::new(RefCell::new(self)))
+    }
+    fn as_internal(&self) -> &ValueInternal {
+        &self.internal
+    }
+    fn as_internal_mut(&mut self) -> &mut ValueInternal {
+        &mut self.internal
+    }
+
+    fn get_type(&self) -> Result<Type, TypeError> {
+        match &self.typ {
+            Some(t) => Ok(t.clone()),
+            None => Err(TypeError::new(
+                &TypecheckContext::new(),
+                TypeMessage::Untyped,
             )),
-            ValueF::PartialExpr(e) => {
-                rc(e.map_ref(|v| v.normalize_to_expr_maybe_alpha(alpha)))
-            }
         }
     }
+}
 
+impl Value {
+    pub(crate) fn from_valuef(v: ValueF) -> Value {
+        ValueInternal::ValueF(WHNF, v).into_value(None)
+    }
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Value {
+        ValueInternal::ValueF(WHNF, v).into_value(Some(t))
+    }
+    pub(crate) fn from_partial_expr(e: ExprF<Value, Normalized>) -> Value {
+        ValueInternal::PartialExpr(e).into_value(None)
+    }
+    pub(crate) fn with_type(self, t: Type) -> Value {
+        self.as_internal().clone().into_value(Some(t))
+    }
+
+    /// Mutates the contents. If no one else shares this thunk,
+    /// mutates directly, thus avoiding a RefCell lock.
+    fn mutate_internal(&mut self, f: impl FnOnce(&mut TypedValueInternal)) {
+        match Rc::get_mut(&mut self.0) {
+            // Mutate directly if sole owner
+            Some(refcell) => f(RefCell::get_mut(refcell)),
+            // Otherwise mutate through the refcell
+            None => f(&mut self.as_tinternal_mut()),
+        }
+    }
+
+    /// Normalizes contents to normal form; faster than `normalize_nf` if
+    /// no one else shares this thunk
     pub(crate) fn normalize_mut(&mut self) {
-        match self {
-            ValueF::Var(_)
-            | ValueF::Const(_)
-            | ValueF::BoolLit(_)
-            | ValueF::NaturalLit(_)
-            | ValueF::IntegerLit(_)
-            | ValueF::DoubleLit(_) => {}
-
-            ValueF::EmptyOptionalLit(tth) | ValueF::EmptyListLit(tth) => {
-                tth.normalize_mut();
-            }
+        self.mutate_internal(|i| i.as_internal_mut().normalize_nf())
+    }
 
-            ValueF::NEOptionalLit(th) => {
-                th.normalize_mut();
-            }
-            ValueF::Lam(_, t, e) => {
-                t.normalize_mut();
-                e.normalize_mut();
-            }
-            ValueF::Pi(_, t, e) => {
-                t.normalize_mut();
-                e.normalize_mut();
-            }
-            ValueF::AppliedBuiltin(_, args) => {
-                for x in args.iter_mut() {
-                    x.normalize_mut();
-                }
-            }
-            ValueF::NEListLit(elts) => {
-                for x in elts.iter_mut() {
-                    x.normalize_mut();
-                }
-            }
-            ValueF::RecordLit(kvs) => {
-                for x in kvs.values_mut() {
-                    x.normalize_mut();
-                }
-            }
-            ValueF::RecordType(kvs) => {
-                for x in kvs.values_mut() {
-                    x.normalize_mut();
-                }
-            }
-            ValueF::UnionType(kts) | ValueF::UnionConstructor(_, kts) => {
-                for x in kts.values_mut().flat_map(|opt| opt) {
-                    x.normalize_mut();
-                }
-            }
-            ValueF::UnionLit(_, v, kts) => {
-                v.normalize_mut();
-                for x in kts.values_mut().flat_map(|opt| opt) {
-                    x.normalize_mut();
-                }
-            }
-            ValueF::TextLit(elts) => {
-                for x in elts.iter_mut() {
-                    use InterpolatedTextContents::{Expr, Text};
-                    match x {
-                        Expr(n) => n.normalize_mut(),
-                        Text(_) => {}
-                    }
-                }
-            }
-            ValueF::Equivalence(x, y) => {
-                x.normalize_mut();
-                y.normalize_mut();
-            }
-            ValueF::PartialExpr(e) => {
-                // TODO: need map_mut
-                e.map_ref(|v| {
-                    v.normalize_nf();
-                });
-            }
+    fn as_tinternal(&self) -> Ref<TypedValueInternal> {
+        self.0.borrow()
+    }
+    fn as_tinternal_mut(&mut self) -> RefMut<TypedValueInternal> {
+        self.0.borrow_mut()
+    }
+    fn as_internal(&self) -> Ref<ValueInternal> {
+        Ref::map(self.as_tinternal(), TypedValueInternal::as_internal)
+    }
+    fn as_internal_mut(&self) -> RefMut<ValueInternal> {
+        RefMut::map(self.0.borrow_mut(), TypedValueInternal::as_internal_mut)
+    }
+
+    fn do_normalize_whnf(&self) {
+        let borrow = self.as_internal();
+        match &*borrow {
+            ValueInternal::PartialExpr(_) => {
+                drop(borrow);
+                self.as_internal_mut().normalize_whnf();
+            }
+            // Already at least in WHNF
+            ValueInternal::ValueF(_, _) => {}
         }
     }
 
-    /// Apply to a value
-    pub(crate) fn app(self, val: ValueF) -> ValueF {
-        self.app_val(val)
+    fn do_normalize_nf(&self) {
+        let borrow = self.as_internal();
+        match &*borrow {
+            ValueInternal::PartialExpr(_) | ValueInternal::ValueF(WHNF, _) => {
+                drop(borrow);
+                self.as_internal_mut().normalize_nf();
+            }
+            // Already in NF
+            ValueInternal::ValueF(NF, _) => {}
+        }
     }
 
-    /// Apply to a value
-    pub(crate) fn app_val(self, val: ValueF) -> ValueF {
-        self.app_thunk(val.into_thunk())
+    // WARNING: avoid normalizing any thunk while holding on to this ref
+    // or you could run into BorrowMut panics
+    pub(crate) fn normalize_nf(&self) -> Ref<ValueF> {
+        self.do_normalize_nf();
+        Ref::map(self.as_internal(), ValueInternal::as_nf)
     }
 
-    /// Apply to a thunk
-    pub fn app_thunk(self, th: Thunk) -> ValueF {
-        Thunk::from_valuef(self).app_thunk(th)
+    // WARNING: avoid normalizing any thunk while holding on to this ref
+    // or you could run into BorrowMut panics
+    pub(crate) fn as_valuef(&self) -> Ref<ValueF> {
+        self.do_normalize_whnf();
+        Ref::map(self.as_internal(), ValueInternal::as_whnf)
     }
 
-    pub fn from_builtin(b: Builtin) -> ValueF {
-        ValueF::AppliedBuiltin(b, vec![])
+    pub(crate) fn to_valuef(&self) -> ValueF {
+        self.as_valuef().clone()
+    }
+
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
+        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
+    }
+
+    pub(crate) fn app_valuef(&self, val: ValueF) -> ValueF {
+        self.app_value(val.into_value())
+    }
+
+    pub(crate) fn app_value(&self, th: Value) -> ValueF {
+        apply_any(self.clone(), th)
+    }
+
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+        Ok(Cow::Owned(self.as_tinternal().get_type()?))
     }
 }
 
-impl Shift for ValueF {
+impl TypedValue {
+    pub(crate) fn from_valuef(v: ValueF) -> TypedValue {
+        TypedValue::from_value_untyped(Value::from_valuef(v))
+    }
+
+    pub(crate) fn from_type(t: Type) -> TypedValue {
+        t.into_typedvalue()
+    }
+
+    pub(crate) fn normalize_nf(&self) -> ValueF {
+        self.0.normalize_nf().clone()
+    }
+
+    pub(crate) fn to_typed(&self) -> Typed {
+        self.clone().into_typed()
+    }
+
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
+        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
+    }
+
+    pub(crate) fn from_value_and_type(th: Value, t: Type) -> Self {
+        TypedValue(th.with_type(t))
+    }
+    pub fn from_value_simple_type(th: Value) -> Self {
+        TypedValue::from_value_and_type(th, Type::const_type())
+    }
+    pub(crate) fn from_value_untyped(th: Value) -> Self {
+        TypedValue(th)
+    }
+    pub(crate) fn from_const(c: Const) -> Self {
+        match type_of_const(c) {
+            Ok(t) => TypedValue::from_valuef_and_type(ValueF::Const(c), t),
+            Err(_) => TypedValue::from_valuef(ValueF::Const(c)),
+        }
+    }
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
+        TypedValue(Value::from_valuef_and_type(v, t))
+    }
+
+    pub(crate) fn to_valuef(&self) -> ValueF {
+        self.0.to_valuef()
+    }
+    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
+        self.to_valuef().normalize_to_expr()
+    }
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
+        self.to_valuef().normalize_to_expr_maybe_alpha(true)
+    }
+    pub(crate) fn to_value(&self) -> Value {
+        self.0.clone()
+    }
+    pub(crate) fn to_type(&self) -> Type {
+        self.clone().into_typed().into_type()
+    }
+    pub(crate) fn into_typed(self) -> Typed {
+        Typed::from_typedvalue(self)
+    }
+    pub(crate) fn as_const(&self) -> Option<Const> {
+        // TODO: avoid clone
+        match &self.to_valuef() {
+            ValueF::Const(c) => Some(*c),
+            _ => None,
+        }
+    }
+
+    pub(crate) fn normalize_mut(&mut self) {
+        self.0.normalize_mut()
+    }
+
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+        self.0.get_type()
+    }
+}
+
+impl Shift for Value {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(Value(self.0.shift(delta, var)?))
+    }
+}
+
+impl Shift for ValueInternal {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
-            ValueF::Lam(x, t, e) => ValueF::Lam(
-                x.clone(),
-                t.shift(delta, var)?,
-                e.shift(delta, &var.under_binder(x))?,
-            ),
-            ValueF::AppliedBuiltin(b, args) => {
-                ValueF::AppliedBuiltin(*b, args.shift(delta, var)?)
-            }
-            ValueF::Pi(x, t, e) => ValueF::Pi(
-                x.clone(),
-                t.shift(delta, var)?,
-                e.shift(delta, &var.under_binder(x))?,
-            ),
-            ValueF::Var(v) => ValueF::Var(v.shift(delta, var)?),
-            ValueF::Const(c) => ValueF::Const(*c),
-            ValueF::BoolLit(b) => ValueF::BoolLit(*b),
-            ValueF::NaturalLit(n) => ValueF::NaturalLit(*n),
-            ValueF::IntegerLit(n) => ValueF::IntegerLit(*n),
-            ValueF::DoubleLit(n) => ValueF::DoubleLit(*n),
-            ValueF::EmptyOptionalLit(tth) => {
-                ValueF::EmptyOptionalLit(tth.shift(delta, var)?)
-            }
-            ValueF::NEOptionalLit(th) => {
-                ValueF::NEOptionalLit(th.shift(delta, var)?)
+            ValueInternal::PartialExpr(e) => {
+                ValueInternal::PartialExpr(e.shift(delta, var)?)
             }
-            ValueF::EmptyListLit(tth) => {
-                ValueF::EmptyListLit(tth.shift(delta, var)?)
+            ValueInternal::ValueF(m, v) => {
+                ValueInternal::ValueF(*m, v.shift(delta, var)?)
             }
-            ValueF::NEListLit(elts) => {
-                ValueF::NEListLit(elts.shift(delta, var)?)
-            }
-            ValueF::RecordLit(kvs) => ValueF::RecordLit(kvs.shift(delta, var)?),
-            ValueF::RecordType(kvs) => {
-                ValueF::RecordType(kvs.shift(delta, var)?)
-            }
-            ValueF::UnionType(kts) => ValueF::UnionType(kts.shift(delta, var)?),
-            ValueF::UnionConstructor(x, kts) => {
-                ValueF::UnionConstructor(x.clone(), kts.shift(delta, var)?)
-            }
-            ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
-                x.clone(),
-                v.shift(delta, var)?,
-                kts.shift(delta, var)?,
-            ),
-            ValueF::TextLit(elts) => ValueF::TextLit(elts.shift(delta, var)?),
-            ValueF::Equivalence(x, y) => {
-                ValueF::Equivalence(x.shift(delta, var)?, y.shift(delta, var)?)
-            }
-            ValueF::PartialExpr(e) => ValueF::PartialExpr(e.shift(delta, var)?),
         })
     }
 }
 
-impl Subst<Typed> for ValueF {
+impl Shift for TypedValue {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(TypedValue(self.0.shift(delta, var)?))
+    }
+}
+
+impl Shift for TypedValueInternal {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(TypedValueInternal {
+            internal: self.internal.shift(delta, var)?,
+            typ: self.typ.shift(delta, var)?,
+        })
+    }
+}
+
+impl Subst<Typed> for Value {
+    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        Value(self.0.subst_shift(var, val))
+    }
+}
+
+impl Subst<Typed> for ValueInternal {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
-            // Retry normalizing since substituting may allow progress
-            ValueF::AppliedBuiltin(b, args) => {
-                apply_builtin(*b, args.subst_shift(var, val))
-            }
-            // Retry normalizing since substituting may allow progress
-            ValueF::PartialExpr(e) => {
-                normalize_one_layer(e.subst_shift(var, val))
-            }
-            // Retry normalizing since substituting may allow progress
-            ValueF::TextLit(elts) => ValueF::TextLit(squash_textlit(
-                elts.iter().map(|contents| contents.subst_shift(var, val)),
-            )),
-            ValueF::Lam(x, t, e) => ValueF::Lam(
-                x.clone(),
-                t.subst_shift(var, val),
-                e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
-            ),
-            ValueF::Pi(x, t, e) => ValueF::Pi(
-                x.clone(),
-                t.subst_shift(var, val),
-                e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
-            ),
-            ValueF::Var(v) if v == var => val.to_valuef(),
-            ValueF::Var(v) => ValueF::Var(v.shift(-1, var).unwrap()),
-            ValueF::Const(c) => ValueF::Const(*c),
-            ValueF::BoolLit(b) => ValueF::BoolLit(*b),
-            ValueF::NaturalLit(n) => ValueF::NaturalLit(*n),
-            ValueF::IntegerLit(n) => ValueF::IntegerLit(*n),
-            ValueF::DoubleLit(n) => ValueF::DoubleLit(*n),
-            ValueF::EmptyOptionalLit(tth) => {
-                ValueF::EmptyOptionalLit(tth.subst_shift(var, val))
-            }
-            ValueF::NEOptionalLit(th) => {
-                ValueF::NEOptionalLit(th.subst_shift(var, val))
-            }
-            ValueF::EmptyListLit(tth) => {
-                ValueF::EmptyListLit(tth.subst_shift(var, val))
+            ValueInternal::PartialExpr(e) => {
+                ValueInternal::PartialExpr(e.subst_shift(var, val))
             }
-            ValueF::NEListLit(elts) => {
-                ValueF::NEListLit(elts.subst_shift(var, val))
+            ValueInternal::ValueF(_, v) => {
+                // The resulting value may not stay in normal form after substitution
+                ValueInternal::ValueF(WHNF, v.subst_shift(var, val))
             }
-            ValueF::RecordLit(kvs) => {
-                ValueF::RecordLit(kvs.subst_shift(var, val))
-            }
-            ValueF::RecordType(kvs) => {
-                ValueF::RecordType(kvs.subst_shift(var, val))
-            }
-            ValueF::UnionType(kts) => {
-                ValueF::UnionType(kts.subst_shift(var, val))
+        }
+    }
+}
+
+impl Subst<Typed> for TypedValueInternal {
+    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        TypedValueInternal {
+            internal: self.internal.subst_shift(var, val),
+            typ: self.typ.subst_shift(var, val),
+        }
+    }
+}
+
+impl Subst<Typed> for TypedValue {
+    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        TypedValue(self.0.subst_shift(var, val))
+    }
+}
+
+impl std::cmp::PartialEq for Value {
+    fn eq(&self, other: &Self) -> bool {
+        *self.as_valuef() == *other.as_valuef()
+    }
+}
+impl std::cmp::Eq for Value {}
+
+impl std::cmp::PartialEq for TypedValue {
+    fn eq(&self, other: &Self) -> bool {
+        self.to_valuef() == other.to_valuef()
+    }
+}
+impl std::cmp::Eq for TypedValue {}
+
+impl std::fmt::Debug for Value {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let b: &ValueInternal = &self.as_internal();
+        match b {
+            ValueInternal::ValueF(m, v) => {
+                f.debug_tuple(&format!("Value@{:?}", m)).field(v).finish()
             }
-            ValueF::UnionConstructor(x, kts) => {
-                ValueF::UnionConstructor(x.clone(), kts.subst_shift(var, val))
+            ValueInternal::PartialExpr(e) => {
+                f.debug_tuple("Value@PartialExpr").field(e).finish()
             }
-            ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
-                x.clone(),
-                v.subst_shift(var, val),
-                kts.subst_shift(var, val),
-            ),
-            ValueF::Equivalence(x, y) => ValueF::Equivalence(
-                x.subst_shift(var, val),
-                y.subst_shift(var, val),
-            ),
         }
     }
 }
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
new file mode 100644
index 0000000..bea2e2e
--- /dev/null
+++ b/dhall/src/core/valuef.rs
@@ -0,0 +1,405 @@
+use std::collections::HashMap;
+
+use dhall_syntax::{
+    rc, Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label,
+    NaiveDouble, Natural,
+};
+
+use crate::core::value::{TypedValue, Value};
+use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
+use crate::phase::normalize::{
+    apply_builtin, normalize_one_layer, squash_textlit, OutputSubExpr,
+};
+use crate::phase::{Normalized, Typed};
+
+/// A semantic value. The invariants ensure this value represents a Weak-Head
+/// Normal Form (WHNF). This means that this first constructor is the first constructor of the
+/// final Normal Form (NF).
+/// This WHNF must be preserved by operations on `ValueF`s. In particular, `subst_shift` could break
+/// the invariants so need to be careful to reevaluate as needed.
+/// Subexpressions are Values, which are partially evaluated expressions that are normalized
+/// on-demand. When all the Values in a ValueF are at least in WHNF, and recursively so, then the
+/// ValueF is in NF. This is because WHNF ensures that we have the first constructor of the NF; so
+/// if we have the first constructor of the NF at all levels, we actually have the NF.
+/// Equality is up to alpha-equivalence (renaming of bound variables) and beta-equivalence
+/// (normalization). Equality will normalize only as needed.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ValueF {
+    /// Closures
+    Lam(AlphaLabel, TypedValue, Value),
+    Pi(AlphaLabel, TypedValue, TypedValue),
+    // Invariant: the evaluation must not be able to progress further.
+    AppliedBuiltin(Builtin, Vec<Value>),
+
+    Var(AlphaVar),
+    Const(Const),
+    BoolLit(bool),
+    NaturalLit(Natural),
+    IntegerLit(Integer),
+    DoubleLit(NaiveDouble),
+    EmptyOptionalLit(TypedValue),
+    NEOptionalLit(Value),
+    // EmptyListLit(t) means `[] : List t`, not `[] : t`
+    EmptyListLit(TypedValue),
+    NEListLit(Vec<Value>),
+    RecordLit(HashMap<Label, Value>),
+    RecordType(HashMap<Label, TypedValue>),
+    UnionType(HashMap<Label, Option<TypedValue>>),
+    UnionConstructor(Label, HashMap<Label, Option<TypedValue>>),
+    UnionLit(Label, Value, HashMap<Label, Option<TypedValue>>),
+    // Invariant: this must not contain interpolations that are themselves TextLits, and
+    // contiguous text values must be merged.
+    TextLit(Vec<InterpolatedTextContents<Value>>),
+    Equivalence(TypedValue, TypedValue),
+    // Invariant: this must not contain a value captured by one of the variants above.
+    PartialExpr(ExprF<Value, Normalized>),
+}
+
+impl ValueF {
+    pub(crate) fn into_value(self) -> Value {
+        Value::from_valuef(self)
+    }
+
+    /// Convert the value to a fully normalized syntactic expression
+    pub(crate) fn normalize_to_expr(&self) -> OutputSubExpr {
+        self.normalize_to_expr_maybe_alpha(false)
+    }
+    /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
+    /// if alpha is `true`
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
+        match self {
+            ValueF::Lam(x, t, e) => rc(ExprF::Lam(
+                x.to_label_maybe_alpha(alpha),
+                t.normalize_to_expr_maybe_alpha(alpha),
+                e.normalize_to_expr_maybe_alpha(alpha),
+            )),
+            ValueF::AppliedBuiltin(b, args) => {
+                let mut e = rc(ExprF::Builtin(*b));
+                for v in args {
+                    e = rc(ExprF::App(
+                        e,
+                        v.normalize_to_expr_maybe_alpha(alpha),
+                    ));
+                }
+                e
+            }
+            ValueF::Pi(x, t, e) => rc(ExprF::Pi(
+                x.to_label_maybe_alpha(alpha),
+                t.normalize_to_expr_maybe_alpha(alpha),
+                e.normalize_to_expr_maybe_alpha(alpha),
+            )),
+            ValueF::Var(v) => rc(ExprF::Var(v.to_var(alpha))),
+            ValueF::Const(c) => rc(ExprF::Const(*c)),
+            ValueF::BoolLit(b) => rc(ExprF::BoolLit(*b)),
+            ValueF::NaturalLit(n) => rc(ExprF::NaturalLit(*n)),
+            ValueF::IntegerLit(n) => rc(ExprF::IntegerLit(*n)),
+            ValueF::DoubleLit(n) => rc(ExprF::DoubleLit(*n)),
+            ValueF::EmptyOptionalLit(n) => rc(ExprF::App(
+                rc(ExprF::Builtin(Builtin::OptionalNone)),
+                n.normalize_to_expr_maybe_alpha(alpha),
+            )),
+            ValueF::NEOptionalLit(n) => {
+                rc(ExprF::SomeLit(n.normalize_to_expr_maybe_alpha(alpha)))
+            }
+            ValueF::EmptyListLit(n) => rc(ExprF::EmptyListLit(rc(ExprF::App(
+                rc(ExprF::Builtin(Builtin::List)),
+                n.normalize_to_expr_maybe_alpha(alpha),
+            )))),
+            ValueF::NEListLit(elts) => rc(ExprF::NEListLit(
+                elts.iter()
+                    .map(|n| n.normalize_to_expr_maybe_alpha(alpha))
+                    .collect(),
+            )),
+            ValueF::RecordLit(kvs) => rc(ExprF::RecordLit(
+                kvs.iter()
+                    .map(|(k, v)| {
+                        (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
+                    })
+                    .collect(),
+            )),
+            ValueF::RecordType(kts) => rc(ExprF::RecordType(
+                kts.iter()
+                    .map(|(k, v)| {
+                        (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
+                    })
+                    .collect(),
+            )),
+            ValueF::UnionType(kts) => rc(ExprF::UnionType(
+                kts.iter()
+                    .map(|(k, v)| {
+                        (
+                            k.clone(),
+                            v.as_ref().map(|v| {
+                                v.normalize_to_expr_maybe_alpha(alpha)
+                            }),
+                        )
+                    })
+                    .collect(),
+            )),
+            ValueF::UnionConstructor(l, kts) => {
+                let kts = kts
+                    .iter()
+                    .map(|(k, v)| {
+                        (
+                            k.clone(),
+                            v.as_ref().map(|v| {
+                                v.normalize_to_expr_maybe_alpha(alpha)
+                            }),
+                        )
+                    })
+                    .collect();
+                rc(ExprF::Field(rc(ExprF::UnionType(kts)), l.clone()))
+            }
+            ValueF::UnionLit(l, v, kts) => rc(ExprF::App(
+                ValueF::UnionConstructor(l.clone(), kts.clone())
+                    .normalize_to_expr_maybe_alpha(alpha),
+                v.normalize_to_expr_maybe_alpha(alpha),
+            )),
+            ValueF::TextLit(elts) => {
+                use InterpolatedTextContents::{Expr, Text};
+                rc(ExprF::TextLit(
+                    elts.iter()
+                        .map(|contents| match contents {
+                            Expr(e) => {
+                                Expr(e.normalize_to_expr_maybe_alpha(alpha))
+                            }
+                            Text(s) => Text(s.clone()),
+                        })
+                        .collect(),
+                ))
+            }
+            ValueF::Equivalence(x, y) => rc(ExprF::BinOp(
+                dhall_syntax::BinOp::Equivalence,
+                x.normalize_to_expr_maybe_alpha(alpha),
+                y.normalize_to_expr_maybe_alpha(alpha),
+            )),
+            ValueF::PartialExpr(e) => {
+                rc(e.map_ref(|v| v.normalize_to_expr_maybe_alpha(alpha)))
+            }
+        }
+    }
+
+    pub(crate) fn normalize_mut(&mut self) {
+        match self {
+            ValueF::Var(_)
+            | ValueF::Const(_)
+            | ValueF::BoolLit(_)
+            | ValueF::NaturalLit(_)
+            | ValueF::IntegerLit(_)
+            | ValueF::DoubleLit(_) => {}
+
+            ValueF::EmptyOptionalLit(tth) | ValueF::EmptyListLit(tth) => {
+                tth.normalize_mut();
+            }
+
+            ValueF::NEOptionalLit(th) => {
+                th.normalize_mut();
+            }
+            ValueF::Lam(_, t, e) => {
+                t.normalize_mut();
+                e.normalize_mut();
+            }
+            ValueF::Pi(_, t, e) => {
+                t.normalize_mut();
+                e.normalize_mut();
+            }
+            ValueF::AppliedBuiltin(_, args) => {
+                for x in args.iter_mut() {
+                    x.normalize_mut();
+                }
+            }
+            ValueF::NEListLit(elts) => {
+                for x in elts.iter_mut() {
+                    x.normalize_mut();
+                }
+            }
+            ValueF::RecordLit(kvs) => {
+                for x in kvs.values_mut() {
+                    x.normalize_mut();
+                }
+            }
+            ValueF::RecordType(kvs) => {
+                for x in kvs.values_mut() {
+                    x.normalize_mut();
+                }
+            }
+            ValueF::UnionType(kts) | ValueF::UnionConstructor(_, kts) => {
+                for x in kts.values_mut().flat_map(|opt| opt) {
+                    x.normalize_mut();
+                }
+            }
+            ValueF::UnionLit(_, v, kts) => {
+                v.normalize_mut();
+                for x in kts.values_mut().flat_map(|opt| opt) {
+                    x.normalize_mut();
+                }
+            }
+            ValueF::TextLit(elts) => {
+                for x in elts.iter_mut() {
+                    use InterpolatedTextContents::{Expr, Text};
+                    match x {
+                        Expr(n) => n.normalize_mut(),
+                        Text(_) => {}
+                    }
+                }
+            }
+            ValueF::Equivalence(x, y) => {
+                x.normalize_mut();
+                y.normalize_mut();
+            }
+            ValueF::PartialExpr(e) => {
+                // TODO: need map_mut
+                e.map_ref(|v| {
+                    v.normalize_nf();
+                });
+            }
+        }
+    }
+
+    /// Apply to a value
+    pub(crate) fn app(self, val: ValueF) -> ValueF {
+        self.app_valuef(val)
+    }
+
+    /// Apply to a value
+    pub(crate) fn app_valuef(self, val: ValueF) -> ValueF {
+        self.app_value(val.into_value())
+    }
+
+    /// Apply to a thunk
+    pub fn app_value(self, th: Value) -> ValueF {
+        Value::from_valuef(self).app_value(th)
+    }
+
+    pub fn from_builtin(b: Builtin) -> ValueF {
+        ValueF::AppliedBuiltin(b, vec![])
+    }
+}
+
+impl Shift for ValueF {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
+        Some(match self {
+            ValueF::Lam(x, t, e) => ValueF::Lam(
+                x.clone(),
+                t.shift(delta, var)?,
+                e.shift(delta, &var.under_binder(x))?,
+            ),
+            ValueF::AppliedBuiltin(b, args) => {
+                ValueF::AppliedBuiltin(*b, args.shift(delta, var)?)
+            }
+            ValueF::Pi(x, t, e) => ValueF::Pi(
+                x.clone(),
+                t.shift(delta, var)?,
+                e.shift(delta, &var.under_binder(x))?,
+            ),
+            ValueF::Var(v) => ValueF::Var(v.shift(delta, var)?),
+            ValueF::Const(c) => ValueF::Const(*c),
+            ValueF::BoolLit(b) => ValueF::BoolLit(*b),
+            ValueF::NaturalLit(n) => ValueF::NaturalLit(*n),
+            ValueF::IntegerLit(n) => ValueF::IntegerLit(*n),
+            ValueF::DoubleLit(n) => ValueF::DoubleLit(*n),
+            ValueF::EmptyOptionalLit(tth) => {
+                ValueF::EmptyOptionalLit(tth.shift(delta, var)?)
+            }
+            ValueF::NEOptionalLit(th) => {
+                ValueF::NEOptionalLit(th.shift(delta, var)?)
+            }
+            ValueF::EmptyListLit(tth) => {
+                ValueF::EmptyListLit(tth.shift(delta, var)?)
+            }
+            ValueF::NEListLit(elts) => {
+                ValueF::NEListLit(elts.shift(delta, var)?)
+            }
+            ValueF::RecordLit(kvs) => ValueF::RecordLit(kvs.shift(delta, var)?),
+            ValueF::RecordType(kvs) => {
+                ValueF::RecordType(kvs.shift(delta, var)?)
+            }
+            ValueF::UnionType(kts) => ValueF::UnionType(kts.shift(delta, var)?),
+            ValueF::UnionConstructor(x, kts) => {
+                ValueF::UnionConstructor(x.clone(), kts.shift(delta, var)?)
+            }
+            ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
+                x.clone(),
+                v.shift(delta, var)?,
+                kts.shift(delta, var)?,
+            ),
+            ValueF::TextLit(elts) => ValueF::TextLit(elts.shift(delta, var)?),
+            ValueF::Equivalence(x, y) => {
+                ValueF::Equivalence(x.shift(delta, var)?, y.shift(delta, var)?)
+            }
+            ValueF::PartialExpr(e) => ValueF::PartialExpr(e.shift(delta, var)?),
+        })
+    }
+}
+
+impl Subst<Typed> for ValueF {
+    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        match self {
+            // Retry normalizing since substituting may allow progress
+            ValueF::AppliedBuiltin(b, args) => {
+                apply_builtin(*b, args.subst_shift(var, val))
+            }
+            // Retry normalizing since substituting may allow progress
+            ValueF::PartialExpr(e) => {
+                normalize_one_layer(e.subst_shift(var, val))
+            }
+            // Retry normalizing since substituting may allow progress
+            ValueF::TextLit(elts) => ValueF::TextLit(squash_textlit(
+                elts.iter().map(|contents| contents.subst_shift(var, val)),
+            )),
+            ValueF::Lam(x, t, e) => ValueF::Lam(
+                x.clone(),
+                t.subst_shift(var, val),
+                e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
+            ),
+            ValueF::Pi(x, t, e) => ValueF::Pi(
+                x.clone(),
+                t.subst_shift(var, val),
+                e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
+            ),
+            ValueF::Var(v) if v == var => val.to_valuef(),
+            ValueF::Var(v) => ValueF::Var(v.shift(-1, var).unwrap()),
+            ValueF::Const(c) => ValueF::Const(*c),
+            ValueF::BoolLit(b) => ValueF::BoolLit(*b),
+            ValueF::NaturalLit(n) => ValueF::NaturalLit(*n),
+            ValueF::IntegerLit(n) => ValueF::IntegerLit(*n),
+            ValueF::DoubleLit(n) => ValueF::DoubleLit(*n),
+            ValueF::EmptyOptionalLit(tth) => {
+                ValueF::EmptyOptionalLit(tth.subst_shift(var, val))
+            }
+            ValueF::NEOptionalLit(th) => {
+                ValueF::NEOptionalLit(th.subst_shift(var, val))
+            }
+            ValueF::EmptyListLit(tth) => {
+                ValueF::EmptyListLit(tth.subst_shift(var, val))
+            }
+            ValueF::NEListLit(elts) => {
+                ValueF::NEListLit(elts.subst_shift(var, val))
+            }
+            ValueF::RecordLit(kvs) => {
+                ValueF::RecordLit(kvs.subst_shift(var, val))
+            }
+            ValueF::RecordType(kvs) => {
+                ValueF::RecordType(kvs.subst_shift(var, val))
+            }
+            ValueF::UnionType(kts) => {
+                ValueF::UnionType(kts.subst_shift(var, val))
+            }
+            ValueF::UnionConstructor(x, kts) => {
+                ValueF::UnionConstructor(x.clone(), kts.subst_shift(var, val))
+            }
+            ValueF::UnionLit(x, v, kts) => ValueF::UnionLit(
+                x.clone(),
+                v.subst_shift(var, val),
+                kts.subst_shift(var, val),
+            ),
+            ValueF::Equivalence(x, y) => ValueF::Equivalence(
+                x.subst_shift(var, val),
+                y.subst_shift(var, val),
+            ),
+        }
+    }
+}
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 7e74f95..c18f976 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -4,8 +4,8 @@ use std::path::Path;
 
 use dhall_syntax::{Const, SubExpr};
 
-use crate::core::thunk::{Thunk, TypedThunk};
-use crate::core::value::ValueF;
+use crate::core::value::{TypedValue, Value};
+use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{EncodeError, Error, ImportError, TypeError};
 
@@ -33,7 +33,7 @@ pub struct Resolved(ResolvedSubExpr);
 
 /// A typed expression
 #[derive(Debug, Clone)]
-pub struct Typed(TypedThunk);
+pub struct Typed(TypedValue);
 
 /// A normalized expression.
 ///
@@ -92,19 +92,19 @@ impl Typed {
         Normalized(self)
     }
 
-    pub(crate) fn from_thunk_and_type(th: Thunk, t: Type) -> Self {
-        Typed(TypedThunk::from_thunk_and_type(th, t))
+    pub(crate) fn from_value_and_type(th: Value, t: Type) -> Self {
+        Typed(TypedValue::from_value_and_type(th, t))
     }
-    pub(crate) fn from_thunk_untyped(th: Thunk) -> Self {
-        Typed(TypedThunk::from_thunk_untyped(th))
+    pub(crate) fn from_value_untyped(th: Value) -> Self {
+        Typed(TypedValue::from_value_untyped(th))
     }
     pub(crate) fn from_const(c: Const) -> Self {
-        Typed(TypedThunk::from_const(c))
+        Typed(TypedValue::from_const(c))
     }
     pub fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
-        Typed(TypedThunk::from_valuef_and_type(v, t))
+        Typed(TypedValue::from_valuef_and_type(v, t))
     }
-    pub(crate) fn from_typethunk(th: TypedThunk) -> Self {
+    pub(crate) fn from_typedvalue(th: TypedValue) -> Self {
         Typed(th)
     }
     pub fn const_type() -> Self {
@@ -120,8 +120,8 @@ impl Typed {
     pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.0.to_expr_alpha()
     }
-    pub fn to_thunk(&self) -> Thunk {
-        self.0.to_thunk()
+    pub fn to_value(&self) -> Value {
+        self.0.to_value()
     }
     // Deprecated
     pub fn to_type(&self) -> Type {
@@ -131,7 +131,7 @@ impl Typed {
     pub(crate) fn into_type(self) -> Type {
         self
     }
-    pub(crate) fn into_typethunk(self) -> TypedThunk {
+    pub(crate) fn into_typedvalue(self) -> TypedValue {
         self.0
     }
     pub(crate) fn to_normalized(&self) -> Normalized {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index da54726..93f2528 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -5,8 +5,8 @@ use dhall_syntax::{
     NaiveDouble,
 };
 
-use crate::core::thunk::{Thunk, TypedThunk};
-use crate::core::value::ValueF;
+use crate::core::value::{TypedValue, Value};
+use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr, Typed};
 
@@ -20,45 +20,45 @@ macro_rules! make_closure {
             Label::from(stringify!($var)).into(),
             $n
         );
-        ValueF::Var(var).into_thunk()
+        ValueF::Var(var).into_value()
     }};
     // Warning: assumes that $ty, as a dhall value, has type `Type`
     (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
         ValueF::Lam(
             Label::from(stringify!($var)).into(),
-            TypedThunk::from_thunk_simple_type(
+            TypedValue::from_value_simple_type(
                 make_closure!($($ty)*),
             ),
             make_closure!($($rest)*),
-        ).into_thunk()
+        ).into_value()
     };
-    (Natural) => { ValueF::from_builtin(Builtin::Natural).into_thunk() };
+    (Natural) => { ValueF::from_builtin(Builtin::Natural).into_value() };
     (List $($rest:tt)*) => {
         ValueF::from_builtin(Builtin::List)
-            .app_thunk(make_closure!($($rest)*))
-            .into_thunk()
+            .app_value(make_closure!($($rest)*))
+            .into_value()
     };
     (Some $($rest:tt)*) => {
-        ValueF::NEOptionalLit(make_closure!($($rest)*)).into_thunk()
+        ValueF::NEOptionalLit(make_closure!($($rest)*)).into_value()
     };
     (1 + $($rest:tt)*) => {
         ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::NaturalPlus,
             make_closure!($($rest)*),
-            Thunk::from_valuef(ValueF::NaturalLit(1)),
-        )).into_thunk()
+            Value::from_valuef(ValueF::NaturalLit(1)),
+        )).into_value()
     };
     ([ $($head:tt)* ] # $($tail:tt)*) => {
         ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::ListAppend,
-            ValueF::NEListLit(vec![make_closure!($($head)*)]).into_thunk(),
+            ValueF::NEListLit(vec![make_closure!($($head)*)]).into_value(),
             make_closure!($($tail)*),
-        )).into_thunk()
+        )).into_value()
     };
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
+pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
     use dhall_syntax::Builtin::*;
     use ValueF::*;
 
@@ -66,7 +66,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
     let ret = match (b, args.as_slice()) {
         (OptionalNone, [t, r..]) => Ok((
             r,
-            EmptyOptionalLit(TypedThunk::from_thunk_simple_type(t.clone())),
+            EmptyOptionalLit(TypedValue::from_value_simple_type(t.clone())),
         )),
         (NaturalIsZero, [n, r..]) => match &*n.as_valuef() {
             NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
@@ -189,10 +189,10 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
                 let mut kts = HashMap::new();
                 kts.insert(
                     "index".into(),
-                    TypedThunk::from_valuef(ValueF::from_builtin(Natural)),
+                    TypedValue::from_valuef(ValueF::from_builtin(Natural)),
                 );
                 kts.insert("value".into(), t.clone());
-                Ok((r, EmptyListLit(TypedThunk::from_valuef(RecordType(kts)))))
+                Ok((r, EmptyListLit(TypedValue::from_valuef(RecordType(kts)))))
             }
             NEListLit(xs) => {
                 let xs = xs
@@ -201,9 +201,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
                     .map(|(i, e)| {
                         let i = NaturalLit(i);
                         let mut kvs = HashMap::new();
-                        kvs.insert("index".into(), Thunk::from_valuef(i));
+                        kvs.insert("index".into(), Value::from_valuef(i));
                         kvs.insert("value".into(), e.clone());
-                        Thunk::from_valuef(RecordLit(kvs))
+                        Value::from_valuef(RecordLit(kvs))
                     })
                     .collect();
                 Ok((r, NEListLit(xs)))
@@ -222,8 +222,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
             }
             _ => Ok((
                 r,
-                f.app_val(ValueF::from_builtin(List).app_thunk(t.clone()))
-                    .app_thunk({
+                f.app_valuef(ValueF::from_builtin(List).app_value(t.clone()))
+                    .app_value({
                         // Move `t` under new `x` variable
                         let t1 = t.under_binder(Label::from("x"));
                         make_closure!(
@@ -232,9 +232,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
                             [ var(x, 1) ] # var(xs, 0)
                         )
                     })
-                    .app_val(EmptyListLit(TypedThunk::from_thunk_simple_type(
-                        t.clone(),
-                    ))),
+                    .app_valuef(EmptyListLit(
+                        TypedValue::from_value_simple_type(t.clone()),
+                    )),
             )),
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_valuef() {
@@ -244,9 +244,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
                 for x in xs.iter().rev() {
                     v = cons
                         .clone()
-                        .app_thunk(x.clone())
-                        .app_thunk(v)
-                        .into_thunk();
+                        .app_value(x.clone())
+                        .app_value(v)
+                        .into_value();
                 }
                 Ok((r, v.to_valuef()))
             }
@@ -264,17 +264,19 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
             }
             _ => Ok((
                 r,
-                f.app_val(ValueF::from_builtin(Optional).app_thunk(t.clone()))
-                    .app_thunk(make_closure!(λ(x: #t) -> Some var(x, 0)))
-                    .app_val(EmptyOptionalLit(
-                        TypedThunk::from_thunk_simple_type(t.clone()),
-                    )),
+                f.app_valuef(
+                    ValueF::from_builtin(Optional).app_value(t.clone()),
+                )
+                .app_value(make_closure!(λ(x: #t) -> Some var(x, 0)))
+                .app_valuef(EmptyOptionalLit(
+                    TypedValue::from_value_simple_type(t.clone()),
+                )),
             )),
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => {
             match &*v.as_valuef() {
                 EmptyOptionalLit(_) => Ok((r, nothing.to_valuef())),
-                NEOptionalLit(x) => Ok((r, just.app_thunk(x.clone()))),
+                NEOptionalLit(x) => Ok((r, just.app_value(x.clone()))),
                 _ => Err(()),
             }
         }
@@ -290,9 +292,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
             }
             _ => Ok((
                 r,
-                f.app_val(ValueF::from_builtin(Natural))
-                    .app_thunk(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
-                    .app_val(NaturalLit(0)),
+                f.app_valuef(ValueF::from_builtin(Natural))
+                    .app_value(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
+                    .app_valuef(NaturalLit(0)),
             )),
         },
         (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_valuef() {
@@ -300,10 +302,10 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
             NaturalLit(n) => {
                 let fold = ValueF::from_builtin(NaturalFold)
                     .app(NaturalLit(n - 1))
-                    .app_thunk(t.clone())
-                    .app_thunk(succ.clone())
-                    .app_thunk(zero.clone());
-                Ok((r, succ.app_val(fold)))
+                    .app_value(t.clone())
+                    .app_value(succ.clone())
+                    .app_value(zero.clone());
+                Ok((r, succ.app_valuef(fold)))
             }
             _ => Err(()),
         },
@@ -313,7 +315,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
         Ok((unconsumed_args, mut v)) => {
             let n_consumed_args = args.len() - unconsumed_args.len();
             for x in args.into_iter().skip(n_consumed_args) {
-                v = v.app_thunk(x);
+                v = v.app_value(x);
             }
             v
         }
@@ -321,13 +323,13 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> ValueF {
     }
 }
 
-pub(crate) fn apply_any(f: Thunk, a: Thunk) -> ValueF {
-    let fallback = |f: Thunk, a: Thunk| ValueF::PartialExpr(ExprF::App(f, a));
+pub(crate) fn apply_any(f: Value, a: Value) -> ValueF {
+    let fallback = |f: Value, a: Value| ValueF::PartialExpr(ExprF::App(f, a));
 
     let f_borrow = f.as_valuef();
     match &*f_borrow {
         ValueF::Lam(x, _, e) => {
-            let val = Typed::from_thunk_untyped(a);
+            let val = Typed::from_value_untyped(a);
             e.subst_shift(&x.into(), &val).to_valuef()
         }
         ValueF::AppliedBuiltin(b, args) => {
@@ -346,15 +348,15 @@ pub(crate) fn apply_any(f: Thunk, a: Thunk) -> ValueF {
 }
 
 pub(crate) fn squash_textlit(
-    elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>,
-) -> Vec<InterpolatedTextContents<Thunk>> {
+    elts: impl Iterator<Item = InterpolatedTextContents<Value>>,
+) -> Vec<InterpolatedTextContents<Value>> {
     use std::mem::replace;
     use InterpolatedTextContents::{Expr, Text};
 
     fn inner(
-        elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>,
+        elts: impl Iterator<Item = InterpolatedTextContents<Value>>,
         crnt_str: &mut String,
-        ret: &mut Vec<InterpolatedTextContents<Thunk>>,
+        ret: &mut Vec<InterpolatedTextContents<Value>>,
     ) {
         for contents in elts {
             match contents {
@@ -390,9 +392,9 @@ pub(crate) fn squash_textlit(
 // Small helper enum to avoid repetition
 enum Ret<'a> {
     ValueF(ValueF),
-    Thunk(Thunk),
-    ThunkRef(&'a Thunk),
-    Expr(ExprF<Thunk, Normalized>),
+    Value(Value),
+    ValueRef(&'a Value),
+    Expr(ExprF<Value, Normalized>),
 }
 
 /// Performs an intersection of two HashMaps.
@@ -508,7 +510,7 @@ where
     kvs
 }
 
-fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
+fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
     use BinOp::{
         BoolAnd, BoolEQ, BoolNE, BoolOr, Equivalence, ListAppend, NaturalPlus,
         NaturalTimes, RecursiveRecordMerge, RecursiveRecordTypeMerge,
@@ -521,46 +523,46 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
     let x_borrow = x.as_valuef();
     let y_borrow = y.as_valuef();
     Some(match (o, &*x_borrow, &*y_borrow) {
-        (BoolAnd, BoolLit(true), _) => Ret::ThunkRef(y),
-        (BoolAnd, _, BoolLit(true)) => Ret::ThunkRef(x),
+        (BoolAnd, BoolLit(true), _) => Ret::ValueRef(y),
+        (BoolAnd, _, BoolLit(true)) => Ret::ValueRef(x),
         (BoolAnd, BoolLit(false), _) => Ret::ValueF(BoolLit(false)),
         (BoolAnd, _, BoolLit(false)) => Ret::ValueF(BoolLit(false)),
-        (BoolAnd, _, _) if x == y => Ret::ThunkRef(x),
+        (BoolAnd, _, _) if x == y => Ret::ValueRef(x),
         (BoolOr, BoolLit(true), _) => Ret::ValueF(BoolLit(true)),
         (BoolOr, _, BoolLit(true)) => Ret::ValueF(BoolLit(true)),
-        (BoolOr, BoolLit(false), _) => Ret::ThunkRef(y),
-        (BoolOr, _, BoolLit(false)) => Ret::ThunkRef(x),
-        (BoolOr, _, _) if x == y => Ret::ThunkRef(x),
-        (BoolEQ, BoolLit(true), _) => Ret::ThunkRef(y),
-        (BoolEQ, _, BoolLit(true)) => Ret::ThunkRef(x),
+        (BoolOr, BoolLit(false), _) => Ret::ValueRef(y),
+        (BoolOr, _, BoolLit(false)) => Ret::ValueRef(x),
+        (BoolOr, _, _) if x == y => Ret::ValueRef(x),
+        (BoolEQ, BoolLit(true), _) => Ret::ValueRef(y),
+        (BoolEQ, _, BoolLit(true)) => Ret::ValueRef(x),
         (BoolEQ, BoolLit(x), BoolLit(y)) => Ret::ValueF(BoolLit(x == y)),
         (BoolEQ, _, _) if x == y => Ret::ValueF(BoolLit(true)),
-        (BoolNE, BoolLit(false), _) => Ret::ThunkRef(y),
-        (BoolNE, _, BoolLit(false)) => Ret::ThunkRef(x),
+        (BoolNE, BoolLit(false), _) => Ret::ValueRef(y),
+        (BoolNE, _, BoolLit(false)) => Ret::ValueRef(x),
         (BoolNE, BoolLit(x), BoolLit(y)) => Ret::ValueF(BoolLit(x != y)),
         (BoolNE, _, _) if x == y => Ret::ValueF(BoolLit(false)),
 
-        (NaturalPlus, NaturalLit(0), _) => Ret::ThunkRef(y),
-        (NaturalPlus, _, NaturalLit(0)) => Ret::ThunkRef(x),
+        (NaturalPlus, NaturalLit(0), _) => Ret::ValueRef(y),
+        (NaturalPlus, _, NaturalLit(0)) => Ret::ValueRef(x),
         (NaturalPlus, NaturalLit(x), NaturalLit(y)) => {
             Ret::ValueF(NaturalLit(x + y))
         }
         (NaturalTimes, NaturalLit(0), _) => Ret::ValueF(NaturalLit(0)),
         (NaturalTimes, _, NaturalLit(0)) => Ret::ValueF(NaturalLit(0)),
-        (NaturalTimes, NaturalLit(1), _) => Ret::ThunkRef(y),
-        (NaturalTimes, _, NaturalLit(1)) => Ret::ThunkRef(x),
+        (NaturalTimes, NaturalLit(1), _) => Ret::ValueRef(y),
+        (NaturalTimes, _, NaturalLit(1)) => Ret::ValueRef(x),
         (NaturalTimes, NaturalLit(x), NaturalLit(y)) => {
             Ret::ValueF(NaturalLit(x * y))
         }
 
-        (ListAppend, EmptyListLit(_), _) => Ret::ThunkRef(y),
-        (ListAppend, _, EmptyListLit(_)) => Ret::ThunkRef(x),
+        (ListAppend, EmptyListLit(_), _) => Ret::ValueRef(y),
+        (ListAppend, _, EmptyListLit(_)) => Ret::ValueRef(x),
         (ListAppend, NEListLit(xs), NEListLit(ys)) => Ret::ValueF(NEListLit(
             xs.iter().chain(ys.iter()).cloned().collect(),
         )),
 
-        (TextAppend, TextLit(x), _) if x.is_empty() => Ret::ThunkRef(y),
-        (TextAppend, _, TextLit(y)) if y.is_empty() => Ret::ThunkRef(x),
+        (TextAppend, TextLit(x), _) if x.is_empty() => Ret::ValueRef(y),
+        (TextAppend, _, TextLit(y)) if y.is_empty() => Ret::ValueRef(x),
         (TextAppend, TextLit(x), TextLit(y)) => Ret::ValueF(TextLit(
             squash_textlit(x.iter().chain(y.iter()).cloned()),
         )),
@@ -580,10 +582,10 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         }
 
         (RightBiasedRecordMerge, _, RecordLit(kvs)) if kvs.is_empty() => {
-            Ret::ThunkRef(x)
+            Ret::ValueRef(x)
         }
         (RightBiasedRecordMerge, RecordLit(kvs), _) if kvs.is_empty() => {
-            Ret::ThunkRef(y)
+            Ret::ValueRef(y)
         }
         (RightBiasedRecordMerge, RecordLit(kvs1), RecordLit(kvs2)) => {
             let mut kvs = kvs2.clone();
@@ -595,14 +597,14 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         }
 
         (RecursiveRecordMerge, _, RecordLit(kvs)) if kvs.is_empty() => {
-            Ret::ThunkRef(x)
+            Ret::ValueRef(x)
         }
         (RecursiveRecordMerge, RecordLit(kvs), _) if kvs.is_empty() => {
-            Ret::ThunkRef(y)
+            Ret::ValueRef(y)
         }
         (RecursiveRecordMerge, RecordLit(kvs1), RecordLit(kvs2)) => {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
-                Thunk::from_partial_expr(ExprF::BinOp(
+                Value::from_partial_expr(ExprF::BinOp(
                     RecursiveRecordMerge,
                     v1.clone(),
                     v2.clone(),
@@ -612,18 +614,18 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         }
 
         (RecursiveRecordTypeMerge, _, RecordType(kvs)) if kvs.is_empty() => {
-            Ret::ThunkRef(x)
+            Ret::ValueRef(x)
         }
         (RecursiveRecordTypeMerge, RecordType(kvs), _) if kvs.is_empty() => {
-            Ret::ThunkRef(y)
+            Ret::ValueRef(y)
         }
         (RecursiveRecordTypeMerge, RecordType(kvs1), RecordType(kvs2)) => {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
-                TypedThunk::from_thunk_untyped(Thunk::from_partial_expr(
+                TypedValue::from_value_untyped(Value::from_partial_expr(
                     ExprF::BinOp(
                         RecursiveRecordTypeMerge,
-                        v1.to_thunk(),
-                        v2.to_thunk(),
+                        v1.to_value(),
+                        v2.to_value(),
                     ),
                 ))
             });
@@ -631,15 +633,15 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> {
         }
 
         (Equivalence, _, _) => Ret::ValueF(ValueF::Equivalence(
-            TypedThunk::from_thunk_simple_type(x.clone()),
-            TypedThunk::from_thunk_simple_type(y.clone()),
+            TypedValue::from_value_simple_type(x.clone()),
+            TypedValue::from_value_simple_type(y.clone()),
         )),
 
         _ => return None,
     })
 }
 
-pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
+pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
     use ValueF::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, Lam,
         NEListLit, NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType,
@@ -652,21 +654,21 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
         ),
         ExprF::Embed(_) => unreachable!(),
         ExprF::Var(_) => unreachable!(),
-        ExprF::Annot(x, _) => Ret::Thunk(x),
+        ExprF::Annot(x, _) => Ret::Value(x),
         ExprF::Assert(_) => Ret::Expr(expr),
         ExprF::Lam(x, t, e) => {
-            Ret::ValueF(Lam(x.into(), TypedThunk::from_thunk_untyped(t), e))
+            Ret::ValueF(Lam(x.into(), TypedValue::from_value_untyped(t), e))
         }
         ExprF::Pi(x, t, e) => Ret::ValueF(Pi(
             x.into(),
-            TypedThunk::from_thunk_untyped(t),
-            TypedThunk::from_thunk_untyped(e),
+            TypedValue::from_value_untyped(t),
+            TypedValue::from_value_untyped(e),
         )),
         ExprF::Let(x, _, v, b) => {
-            let v = Typed::from_thunk_untyped(v);
-            Ret::Thunk(b.subst_shift(&x.into(), &v))
+            let v = Typed::from_value_untyped(v);
+            Ret::Value(b.subst_shift(&x.into(), &v))
         }
-        ExprF::App(v, a) => Ret::ValueF(v.app_thunk(a)),
+        ExprF::App(v, a) => Ret::ValueF(v.app_value(a)),
         ExprF::Builtin(b) => Ret::ValueF(ValueF::from_builtin(b)),
         ExprF::Const(c) => Ret::ValueF(ValueF::Const(c)),
         ExprF::BoolLit(b) => Ret::ValueF(BoolLit(b)),
@@ -680,7 +682,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
             match &*t_borrow {
                 AppliedBuiltin(Builtin::List, args) if args.len() == 1 => {
                     Ret::ValueF(EmptyListLit(
-                        TypedThunk::from_thunk_simple_type(args[0].clone()),
+                        TypedValue::from_value_simple_type(args[0].clone()),
                     ))
                 }
                 _ => {
@@ -697,12 +699,12 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
         }
         ExprF::RecordType(kts) => Ret::ValueF(RecordType(
             kts.into_iter()
-                .map(|(k, t)| (k, TypedThunk::from_thunk_untyped(t)))
+                .map(|(k, t)| (k, TypedValue::from_value_untyped(t)))
                 .collect(),
         )),
         ExprF::UnionType(kts) => Ret::ValueF(UnionType(
             kts.into_iter()
-                .map(|(k, t)| (k, t.map(|t| TypedThunk::from_thunk_untyped(t))))
+                .map(|(k, t)| (k, t.map(|t| TypedValue::from_value_untyped(t))))
                 .collect(),
         )),
         ExprF::TextLit(elts) => {
@@ -710,7 +712,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
             let elts: Vec<_> = squash_textlit(elts.into_iter());
             // Simplify bare interpolation
             if let [Expr(th)] = elts.as_slice() {
-                Ret::Thunk(th.clone())
+                Ret::Value(th.clone())
             } else {
                 Ret::ValueF(TextLit(elts))
             }
@@ -718,15 +720,15 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
         ExprF::BoolIf(ref b, ref e1, ref e2) => {
             let b_borrow = b.as_valuef();
             match &*b_borrow {
-                BoolLit(true) => Ret::ThunkRef(e1),
-                BoolLit(false) => Ret::ThunkRef(e2),
+                BoolLit(true) => Ret::ValueRef(e1),
+                BoolLit(false) => Ret::ValueRef(e2),
                 _ => {
                     let e1_borrow = e1.as_valuef();
                     let e2_borrow = e2.as_valuef();
                     match (&*e1_borrow, &*e2_borrow) {
                         // Simplify `if b then True else False`
-                        (BoolLit(true), BoolLit(false)) => Ret::ThunkRef(b),
-                        _ if e1 == e2 => Ret::ThunkRef(e1),
+                        (BoolLit(true), BoolLit(false)) => Ret::ValueRef(b),
+                        _ if e1 == e2 => Ret::ValueRef(e1),
                         _ => {
                             drop(b_borrow);
                             drop(e1_borrow);
@@ -765,7 +767,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
             let v_borrow = v.as_valuef();
             match &*v_borrow {
                 RecordLit(kvs) => match kvs.get(l) {
-                    Some(r) => Ret::Thunk(r.clone()),
+                    Some(r) => Ret::Value(r.clone()),
                     None => {
                         drop(v_borrow);
                         Ret::Expr(expr)
@@ -786,7 +788,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
             let variant_borrow = variant.as_valuef();
             match (&*handlers_borrow, &*variant_borrow) {
                 (RecordLit(kvs), UnionConstructor(l, _)) => match kvs.get(l) {
-                    Some(h) => Ret::Thunk(h.clone()),
+                    Some(h) => Ret::Value(h.clone()),
                     None => {
                         drop(handlers_borrow);
                         drop(variant_borrow);
@@ -794,7 +796,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
                     }
                 },
                 (RecordLit(kvs), UnionLit(l, v, _)) => match kvs.get(l) {
-                    Some(h) => Ret::ValueF(h.app_thunk(v.clone())),
+                    Some(h) => Ret::ValueF(h.app_value(v.clone())),
                     None => {
                         drop(handlers_borrow);
                         drop(variant_borrow);
@@ -812,8 +814,8 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Normalized>) -> ValueF {
 
     match ret {
         Ret::ValueF(v) => v,
-        Ret::Thunk(th) => th.to_valuef(),
-        Ret::ThunkRef(th) => th.to_valuef(),
+        Ret::Value(th) => th.to_valuef(),
+        Ret::ValueRef(th) => th.to_valuef(),
         Ret::Expr(expr) => ValueF::PartialExpr(expr),
     }
 }
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 8d7a3bc..4154afe 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -5,8 +5,8 @@ use dhall_syntax::{
 };
 
 use crate::core::context::TypecheckContext;
-use crate::core::thunk::{Thunk, TypedThunk};
-use crate::core::value::ValueF;
+use crate::core::value::{TypedValue, Value};
+use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::{Normalized, Resolved, Type, Typed};
@@ -42,13 +42,13 @@ fn tck_pi_type(
 
     let k = function_check(ka, kb);
 
-    Ok(Typed::from_thunk_and_type(
+    Ok(Typed::from_value_and_type(
         ValueF::Pi(
             x.into(),
-            TypedThunk::from_type(tx),
-            TypedThunk::from_type(te),
+            TypedValue::from_type(tx),
+            TypedValue::from_type(te),
         )
-        .into_thunk(),
+        .into_value(),
         Type::from_const(k),
     ))
 }
@@ -80,15 +80,15 @@ fn tck_record_type(
                 return Err(TypeError::new(ctx, RecordTypeDuplicateField))
             }
             Entry::Vacant(_) => {
-                entry.or_insert_with(|| TypedThunk::from_type(t.clone()))
+                entry.or_insert_with(|| TypedValue::from_type(t.clone()))
             }
         };
     }
     // An empty record type has type Type
     let k = k.unwrap_or(dhall_syntax::Const::Type);
 
-    Ok(Typed::from_thunk_and_type(
-        ValueF::RecordType(new_kts).into_thunk(),
+    Ok(Typed::from_value_and_type(
+        ValueF::RecordType(new_kts).into_value(),
         Type::from_const(k),
     ))
 }
@@ -122,7 +122,7 @@ fn tck_union_type(
                 return Err(TypeError::new(ctx, UnionTypeDuplicateField))
             }
             Entry::Vacant(_) => entry.or_insert_with(|| {
-                t.as_ref().map(|t| TypedThunk::from_type(t.clone()))
+                t.as_ref().map(|t| TypedValue::from_type(t.clone()))
             }),
         };
     }
@@ -131,8 +131,8 @@ fn tck_union_type(
     // an union type with only unary variants also has type Type
     let k = k.unwrap_or(dhall_syntax::Const::Type);
 
-    Ok(Typed::from_thunk_and_type(
-        ValueF::UnionType(new_kts).into_thunk(),
+    Ok(Typed::from_value_and_type(
+        ValueF::UnionType(new_kts).into_value(),
         Type::from_const(k),
     ))
 }
@@ -337,12 +337,12 @@ fn type_with(
             let b = type_with(&ctx2, b.clone())?;
             let v = ValueF::Lam(
                 x.clone().into(),
-                TypedThunk::from_type(tx.clone()),
-                b.to_thunk(),
+                TypedValue::from_type(tx.clone()),
+                b.to_value(),
             );
             let tb = b.get_type()?.into_owned();
             let t = tck_pi_type(ctx, x.clone(), tx, tb)?.to_type();
-            Typed::from_thunk_and_type(Thunk::from_valuef(v), t)
+            Typed::from_value_and_type(Value::from_valuef(v), t)
         }
         Pi(x, ta, tb) => {
             let ta = mktype(ctx, ta.clone())?;
@@ -380,9 +380,9 @@ fn type_with(
             let ret = type_last_layer(ctx, &expr)?;
             match ret {
                 RetTypeOnly(typ) => {
-                    let expr = expr.map_ref(|typed| typed.to_thunk());
-                    Typed::from_thunk_and_type(
-                        Thunk::from_partial_expr(expr),
+                    let expr = expr.map_ref(|typed| typed.to_value());
+                    Typed::from_value_and_type(
+                        Value::from_partial_expr(expr),
                         typ,
                     )
                 }
@@ -505,10 +505,10 @@ fn type_last_layer(
             }
 
             Ok(RetTypeOnly(
-                Typed::from_thunk_and_type(
+                Typed::from_value_and_type(
                     ValueF::from_builtin(dhall_syntax::Builtin::List)
                         .app(t.to_valuef())
-                        .into_thunk(),
+                        .into_value(),
                     Typed::from_const(Type),
                 )
                 .to_type(),
@@ -524,10 +524,10 @@ fn type_last_layer(
             }
 
             Ok(RetTypeOnly(
-                Typed::from_thunk_and_type(
+                Typed::from_value_and_type(
                     ValueF::from_builtin(dhall_syntax::Builtin::Optional)
                         .app(t.to_valuef())
-                        .into_thunk(),
+                        .into_value(),
                     Typed::from_const(Type).into_type(),
                 )
                 .to_type(),
@@ -662,8 +662,8 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: HashMap<Label, TypedThunk>,
-                kts_r: HashMap<Label, TypedThunk>,
+                kts_l: HashMap<Label, TypedValue>,
+                kts_r: HashMap<Label, TypedValue>,
             ) -> Result<Typed, TypeError> {
                 use crate::phase::normalize::outer_join;
 
@@ -671,8 +671,8 @@ fn type_last_layer(
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
                 let combine = |k: &Label,
-                               inner_l: &TypedThunk,
-                               inner_r: &TypedThunk|
+                               inner_l: &TypedValue,
+                               inner_r: &TypedValue|
                  -> Result<Typed, TypeError> {
                     match (inner_l.to_valuef(), inner_r.to_valuef()) {
                         (
@@ -690,7 +690,7 @@ fn type_last_layer(
                 let kts: HashMap<Label, Result<Typed, TypeError>> = outer_join(
                     |l| Ok(l.to_type()),
                     |r| Ok(r.to_type()),
-                    |k: &Label, l: &TypedThunk, r: &TypedThunk| {
+                    |k: &Label, l: &TypedValue, r: &TypedValue| {
                         combine(k, l, r)
                     },
                     &kts_l,
@@ -735,8 +735,8 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: HashMap<Label, TypedThunk>,
-                kts_r: HashMap<Label, TypedThunk>,
+                kts_l: HashMap<Label, TypedValue>,
+                kts_r: HashMap<Label, TypedValue>,
             ) -> Result<Typed, TypeError> {
                 use crate::phase::normalize::intersection_with_key;
 
@@ -744,8 +744,8 @@ fn type_last_layer(
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
                 let combine = |k: &Label,
-                               kts_l_inner: &TypedThunk,
-                               kts_r_inner: &TypedThunk|
+                               kts_l_inner: &TypedValue,
+                               kts_r_inner: &TypedValue|
                  -> Result<Typed, TypeError> {
                     match (kts_l_inner.to_valuef(), kts_r_inner.to_valuef()) {
                         (
@@ -761,7 +761,7 @@ fn type_last_layer(
                 };
 
                 let kts = intersection_with_key(
-                    |k: &Label, l: &TypedThunk, r: &TypedThunk| {
+                    |k: &Label, l: &TypedValue, r: &TypedValue| {
                         combine(k, l, r)
                     },
                     &kts_l,
@@ -989,8 +989,8 @@ fn type_last_layer(
             }
 
             Ok(RetTypeOnly(
-                Typed::from_thunk_and_type(
-                    ValueF::RecordType(new_kts).into_thunk(),
+                Typed::from_value_and_type(
+                    ValueF::RecordType(new_kts).into_value(),
                     trecord.get_type()?.into_owned(),
                 )
                 .to_type(),
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 49fd40e..48f311e 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -124,8 +124,9 @@ pub use value::Value;
 
 // A Dhall value.
 pub mod value {
-    use dhall::core::thunk::{Thunk, TypedThunk};
-    use dhall::core::value::ValueF as DhallValue;
+    use dhall::core::value::TypedValue as TypedThunk;
+    use dhall::core::value::Value as Thunk;
+    use dhall::core::valuef::ValueF as DhallValue;
     use dhall::phase::{NormalizedSubExpr, Parsed, Type, Typed};
     use dhall_syntax::Builtin;
 
@@ -153,8 +154,8 @@ pub mod value {
         pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
             self.0.to_expr()
         }
-        pub(crate) fn to_thunk(&self) -> Thunk {
-            self.0.to_thunk()
+        pub(crate) fn to_value(&self) -> Thunk {
+            self.0.to_value()
         }
         pub(crate) fn to_type(&self) -> Type {
             self.0.to_type()
@@ -170,12 +171,12 @@ pub mod value {
         pub(crate) fn make_optional_type(t: Value) -> Self {
             Self::make_simple_type(
                 DhallValue::from_builtin(Builtin::Optional)
-                    .app_thunk(t.to_thunk()),
+                    .app_value(t.to_value()),
             )
         }
         pub(crate) fn make_list_type(t: Value) -> Self {
             Self::make_simple_type(
-                DhallValue::from_builtin(Builtin::List).app_thunk(t.to_thunk()),
+                DhallValue::from_builtin(Builtin::List).app_value(t.to_value()),
             )
         }
         // Made public for the StaticType derive macro
@@ -185,7 +186,7 @@ pub mod value {
         ) -> Self {
             Self::make_simple_type(DhallValue::RecordType(
                 kts.map(|(k, t)| {
-                    (k.into(), TypedThunk::from_thunk_simple_type(t.to_thunk()))
+                    (k.into(), TypedThunk::from_value_simple_type(t.to_value()))
                 })
                 .collect(),
             ))
@@ -199,7 +200,7 @@ pub mod value {
                     (
                         k.into(),
                         t.map(|t| {
-                            TypedThunk::from_thunk_simple_type(t.to_thunk())
+                            TypedThunk::from_value_simple_type(t.to_value())
                         }),
                     )
                 })
-- 
cgit v1.3.1


From c7d9a8659214a228963ea40d76e361bbc08129bb Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 18 Aug 2019 15:24:13 +0200
Subject: Rework ValueInternal and clarify invariants around ValueF

---
 Cargo.lock                   |   1 +
 dhall/Cargo.toml             |   1 +
 dhall/src/core/value.rs      | 103 +++++++++++++++++++++++--------------------
 dhall/src/core/valuef.rs     |  30 ++++---------
 dhall/src/phase/normalize.rs |  29 ++++++++----
 5 files changed, 86 insertions(+), 78 deletions(-)

(limited to 'dhall/src/core')

diff --git a/Cargo.lock b/Cargo.lock
index ccd8520..c073fad 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -75,6 +75,7 @@ dependencies = [
  "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.90 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_cbor 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "term-painter 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
diff --git a/dhall/Cargo.toml b/dhall/Cargo.toml
index 0a257e4..16c1c78 100644
--- a/dhall/Cargo.toml
+++ b/dhall/Cargo.toml
@@ -9,6 +9,7 @@ build = "build.rs"
 [dependencies]
 bytecount = "0.5.1"
 itertools = "0.8.0"
+take_mut = "0.2.2"
 term-painter = "0.2.3"
 serde = { version = "1.0" }
 serde_cbor = "0.9.0"
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 5c29bf0..19976af 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -8,28 +8,32 @@ use crate::core::context::TypecheckContext;
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
-use crate::phase::normalize::{apply_any, normalize_one_layer, OutputSubExpr};
+use crate::phase::normalize::{apply_any, normalize_whnf, OutputSubExpr};
 use crate::phase::typecheck::type_of_const;
 use crate::phase::{Normalized, NormalizedSubExpr, Type, Typed};
 
 #[derive(Debug, Clone, Copy)]
-enum Marker {
-    /// Weak Head Normal Form, i.e. subexpressions may not be normalized
+enum Form {
+    /// No constraints; expression may not be normalized at all.
+    Unevaled,
+    /// Weak Head Normal Form, i.e. normalized up to the first constructor, but subexpressions may
+    /// not be normalized. This means that the first constructor of the contained ValueF is the first
+    /// constructor of the final Normal Form (NF).
     WHNF,
-    /// Normal form, i.e. completely normalized
+    /// Normal Form, i.e. completely normalized.
+    /// When all the Values in a ValueF are at least in WHNF, and recursively so, then the
+    /// ValueF is in NF. This is because WHNF ensures that we have the first constructor of the NF; so
+    /// if we have the first constructor of the NF at all levels, we actually have the NF.
     NF,
 }
-use Marker::{NF, WHNF};
+use Form::{Unevaled, NF, WHNF};
 
 #[derive(Debug, Clone)]
 enum ValueInternal {
-    /// Partially normalized value whose subexpressions have been thunked (this is returned from
-    /// typechecking). Note that this is different from `ValueF::PartialExpr` because there is no
-    /// requirement of WHNF here.
-    PartialExpr(ExprF<Value, Normalized>),
     /// Partially normalized value.
+    /// Invariant: if the marker is `WHNF`, the value must be in Weak Head Normal Form
     /// Invariant: if the marker is `NF`, the value must be fully normalized
-    ValueF(Marker, ValueF),
+    ValueF(Form, ValueF),
 }
 
 #[derive(Debug)]
@@ -45,6 +49,8 @@ struct TypedValueInternal {
 #[derive(Clone)]
 pub struct Value(Rc<RefCell<TypedValueInternal>>);
 
+/// A value that needs to carry a type for typechecking to work.
+/// TODO: actually enforce this.
 #[derive(Debug, Clone)]
 pub struct TypedValue(Value);
 
@@ -58,25 +64,25 @@ impl ValueInternal {
     }
 
     fn normalize_whnf(&mut self) {
-        match self {
-            ValueInternal::PartialExpr(e) => {
-                *self =
-                    ValueInternal::ValueF(WHNF, normalize_one_layer(e.clone()))
+        take_mut::take(self, |vint| match vint {
+            ValueInternal::ValueF(Unevaled, v) => {
+                ValueInternal::ValueF(WHNF, normalize_whnf(v))
             }
-            // Already at least in WHNF
-            ValueInternal::ValueF(_, _) => {}
-        }
+            // Already in WHNF
+            vint @ ValueInternal::ValueF(WHNF, _)
+            | vint @ ValueInternal::ValueF(NF, _) => vint,
+        })
     }
 
     fn normalize_nf(&mut self) {
         match self {
-            ValueInternal::PartialExpr(_) => {
+            ValueInternal::ValueF(Unevaled, _) => {
                 self.normalize_whnf();
                 self.normalize_nf();
             }
-            ValueInternal::ValueF(m @ WHNF, v) => {
+            ValueInternal::ValueF(f @ WHNF, v) => {
                 v.normalize_mut();
-                *m = NF;
+                *f = NF;
             }
             // Already in NF
             ValueInternal::ValueF(NF, _) => {}
@@ -86,7 +92,7 @@ impl ValueInternal {
     // Always use normalize_whnf before
     fn as_whnf(&self) -> &ValueF {
         match self {
-            ValueInternal::PartialExpr(_) => unreachable!(),
+            ValueInternal::ValueF(Unevaled, _) => unreachable!(),
             ValueInternal::ValueF(_, v) => v,
         }
     }
@@ -94,9 +100,8 @@ impl ValueInternal {
     // Always use normalize_nf before
     fn as_nf(&self) -> &ValueF {
         match self {
-            ValueInternal::PartialExpr(_) | ValueInternal::ValueF(WHNF, _) => {
-                unreachable!()
-            }
+            ValueInternal::ValueF(Unevaled, _)
+            | ValueInternal::ValueF(WHNF, _) => unreachable!(),
             ValueInternal::ValueF(NF, v) => v,
         }
     }
@@ -126,13 +131,13 @@ impl TypedValueInternal {
 
 impl Value {
     pub(crate) fn from_valuef(v: ValueF) -> Value {
-        ValueInternal::ValueF(WHNF, v).into_value(None)
+        ValueInternal::ValueF(Unevaled, v).into_value(None)
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Value {
-        ValueInternal::ValueF(WHNF, v).into_value(Some(t))
+        ValueInternal::ValueF(Unevaled, v).into_value(Some(t))
     }
     pub(crate) fn from_partial_expr(e: ExprF<Value, Normalized>) -> Value {
-        ValueInternal::PartialExpr(e).into_value(None)
+        Value::from_valuef(ValueF::PartialExpr(e))
     }
     pub(crate) fn with_type(self, t: Type) -> Value {
         self.as_internal().clone().into_value(Some(t))
@@ -150,7 +155,7 @@ impl Value {
     }
 
     /// Normalizes contents to normal form; faster than `normalize_nf` if
-    /// no one else shares this thunk
+    /// no one else shares this thunk.
     pub(crate) fn normalize_mut(&mut self) {
         self.mutate_internal(|i| i.as_internal_mut().normalize_nf())
     }
@@ -171,19 +176,20 @@ impl Value {
     fn do_normalize_whnf(&self) {
         let borrow = self.as_internal();
         match &*borrow {
-            ValueInternal::PartialExpr(_) => {
+            ValueInternal::ValueF(Unevaled, _) => {
                 drop(borrow);
                 self.as_internal_mut().normalize_whnf();
             }
             // Already at least in WHNF
-            ValueInternal::ValueF(_, _) => {}
+            ValueInternal::ValueF(WHNF, _) | ValueInternal::ValueF(NF, _) => {}
         }
     }
 
     fn do_normalize_nf(&self) {
         let borrow = self.as_internal();
         match &*borrow {
-            ValueInternal::PartialExpr(_) | ValueInternal::ValueF(WHNF, _) => {
+            ValueInternal::ValueF(Unevaled, _)
+            | ValueInternal::ValueF(WHNF, _) => {
                 drop(borrow);
                 self.as_internal_mut().normalize_nf();
             }
@@ -199,13 +205,21 @@ impl Value {
         Ref::map(self.as_internal(), ValueInternal::as_nf)
     }
 
-    // WARNING: avoid normalizing any thunk while holding on to this ref
-    // or you could run into BorrowMut panics
+    /// WARNING: avoid normalizing any thunk while holding on to this ref
+    /// or you could run into BorrowMut panics
+    /// TODO: deprecated because of misleading name
     pub(crate) fn as_valuef(&self) -> Ref<ValueF> {
+        self.as_whnf()
+    }
+
+    /// WARNING: avoid normalizing any thunk while holding on to this ref
+    /// or you could run into BorrowMut panics
+    pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
         self.do_normalize_whnf();
         Ref::map(self.as_internal(), ValueInternal::as_whnf)
     }
 
+    /// TODO: deprecated because of misleading name
     pub(crate) fn to_valuef(&self) -> ValueF {
         self.as_valuef().clone()
     }
@@ -317,11 +331,8 @@ impl Shift for Value {
 impl Shift for ValueInternal {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(match self {
-            ValueInternal::PartialExpr(e) => {
-                ValueInternal::PartialExpr(e.shift(delta, var)?)
-            }
-            ValueInternal::ValueF(m, v) => {
-                ValueInternal::ValueF(*m, v.shift(delta, var)?)
+            ValueInternal::ValueF(f, v) => {
+                ValueInternal::ValueF(*f, v.shift(delta, var)?)
             }
         })
     }
@@ -351,12 +362,9 @@ impl Subst<Typed> for Value {
 impl Subst<Typed> for ValueInternal {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
-            ValueInternal::PartialExpr(e) => {
-                ValueInternal::PartialExpr(e.subst_shift(var, val))
-            }
             ValueInternal::ValueF(_, v) => {
-                // The resulting value may not stay in normal form after substitution
-                ValueInternal::ValueF(WHNF, v.subst_shift(var, val))
+                // The resulting value may not stay in wnhf after substitution
+                ValueInternal::ValueF(Unevaled, v.subst_shift(var, val))
             }
         }
     }
@@ -392,14 +400,11 @@ impl std::cmp::PartialEq for TypedValue {
 impl std::cmp::Eq for TypedValue {}
 
 impl std::fmt::Debug for Value {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let b: &ValueInternal = &self.as_internal();
         match b {
-            ValueInternal::ValueF(m, v) => {
-                f.debug_tuple(&format!("Value@{:?}", m)).field(v).finish()
-            }
-            ValueInternal::PartialExpr(e) => {
-                f.debug_tuple("Value@PartialExpr").field(e).finish()
+            ValueInternal::ValueF(f, v) => {
+                fmt.debug_tuple(&format!("Value@{:?}", f)).field(v).finish()
             }
         }
     }
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index bea2e2e..9e6e8c8 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -7,22 +7,13 @@ use dhall_syntax::{
 
 use crate::core::value::{TypedValue, Value};
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
-use crate::phase::normalize::{
-    apply_builtin, normalize_one_layer, squash_textlit, OutputSubExpr,
-};
+use crate::phase::normalize::OutputSubExpr;
 use crate::phase::{Normalized, Typed};
 
-/// A semantic value. The invariants ensure this value represents a Weak-Head
-/// Normal Form (WHNF). This means that this first constructor is the first constructor of the
-/// final Normal Form (NF).
-/// This WHNF must be preserved by operations on `ValueF`s. In particular, `subst_shift` could break
-/// the invariants so need to be careful to reevaluate as needed.
-/// Subexpressions are Values, which are partially evaluated expressions that are normalized
-/// on-demand. When all the Values in a ValueF are at least in WHNF, and recursively so, then the
-/// ValueF is in NF. This is because WHNF ensures that we have the first constructor of the NF; so
-/// if we have the first constructor of the NF at all levels, we actually have the NF.
+/// A semantic value. Subexpressions are Values, which are partially evaluated expressions that are
+/// normalized on-demand.
 /// Equality is up to alpha-equivalence (renaming of bound variables) and beta-equivalence
-/// (normalization). Equality will normalize only as needed.
+/// (normalization). Equality will normalize as needed.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ValueF {
     /// Closures
@@ -338,18 +329,15 @@ impl Shift for ValueF {
 impl Subst<Typed> for ValueF {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         match self {
-            // Retry normalizing since substituting may allow progress
             ValueF::AppliedBuiltin(b, args) => {
-                apply_builtin(*b, args.subst_shift(var, val))
+                ValueF::AppliedBuiltin(*b, args.subst_shift(var, val))
             }
-            // Retry normalizing since substituting may allow progress
             ValueF::PartialExpr(e) => {
-                normalize_one_layer(e.subst_shift(var, val))
+                ValueF::PartialExpr(e.subst_shift(var, val))
+            }
+            ValueF::TextLit(elts) => {
+                ValueF::TextLit(elts.subst_shift(var, val))
             }
-            // Retry normalizing since substituting may allow progress
-            ValueF::TextLit(elts) => ValueF::TextLit(squash_textlit(
-                elts.iter().map(|contents| contents.subst_shift(var, val)),
-            )),
             ValueF::Lam(x, t, e) => ValueF::Lam(
                 x.clone(),
                 t.subst_shift(var, val),
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 93f2528..6c65e43 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -389,14 +389,6 @@ pub(crate) fn squash_textlit(
     ret
 }
 
-// Small helper enum to avoid repetition
-enum Ret<'a> {
-    ValueF(ValueF),
-    Value(Value),
-    ValueRef(&'a Value),
-    Expr(ExprF<Value, Normalized>),
-}
-
 /// Performs an intersection of two HashMaps.
 ///
 /// # Arguments
@@ -510,6 +502,14 @@ where
     kvs
 }
 
+// Small helper enum to avoid repetition
+enum Ret<'a> {
+    ValueF(ValueF),
+    Value(Value),
+    ValueRef(&'a Value),
+    Expr(ExprF<Value, Normalized>),
+}
+
 fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
     use BinOp::{
         BoolAnd, BoolEQ, BoolNE, BoolOr, Equivalence, ListAppend, NaturalPlus,
@@ -819,3 +819,16 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         Ret::Expr(expr) => ValueF::PartialExpr(expr),
     }
 }
+
+/// Normalize a ValueF into WHNF
+pub(crate) fn normalize_whnf(v: ValueF) -> ValueF {
+    match v {
+        ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args),
+        ValueF::PartialExpr(e) => normalize_one_layer(e),
+        ValueF::TextLit(elts) => {
+            ValueF::TextLit(squash_textlit(elts.into_iter()))
+        }
+        // All other cases are already in WHNF
+        v => v,
+    }
+}
-- 
cgit v1.3.1


From e70da4c0e9ee2354d757f19f1712f5b04f7acc99 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 18 Aug 2019 23:17:03 +0200
Subject: Merge ValueInternal and TypedValueInternal

---
 dhall/src/core/value.rs | 190 ++++++++++++++++++++----------------------------
 1 file changed, 79 insertions(+), 111 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 19976af..ef43e3e 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -29,17 +29,13 @@ enum Form {
 use Form::{Unevaled, NF, WHNF};
 
 #[derive(Debug, Clone)]
-enum ValueInternal {
-    /// Partially normalized value.
-    /// Invariant: if the marker is `WHNF`, the value must be in Weak Head Normal Form
-    /// Invariant: if the marker is `NF`, the value must be fully normalized
-    ValueF(Form, ValueF),
-}
-
-#[derive(Debug)]
-struct TypedValueInternal {
-    internal: ValueInternal,
-    typ: Option<Type>,
+/// Partially normalized value.
+/// Invariant: if `form` is `WHNF`, `value` must be in Weak Head Normal Form
+/// Invariant: if `form` is `NF`, `value` must be fully normalized
+struct ValueInternal {
+    form: Form,
+    value: ValueF,
+    ty: Option<Type>,
 }
 
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
@@ -47,7 +43,7 @@ struct TypedValueInternal {
 /// Can optionally store a Type from typechecking to preserve type information through
 /// normalization.
 #[derive(Clone)]
-pub struct Value(Rc<RefCell<TypedValueInternal>>);
+pub struct Value(Rc<RefCell<ValueInternal>>);
 
 /// A value that needs to carry a type for typechecking to work.
 /// TODO: actually enforce this.
@@ -55,72 +51,54 @@ pub struct Value(Rc<RefCell<TypedValueInternal>>);
 pub struct TypedValue(Value);
 
 impl ValueInternal {
-    fn into_value(self, t: Option<Type>) -> Value {
-        TypedValueInternal {
-            internal: self,
-            typ: t,
-        }
-        .into_value()
+    fn into_value(self) -> Value {
+        Value(Rc::new(RefCell::new(self)))
     }
 
     fn normalize_whnf(&mut self) {
-        take_mut::take(self, |vint| match vint {
-            ValueInternal::ValueF(Unevaled, v) => {
-                ValueInternal::ValueF(WHNF, normalize_whnf(v))
-            }
+        take_mut::take(self, |vint| match &vint.form {
+            Unevaled => ValueInternal {
+                form: WHNF,
+                value: normalize_whnf(vint.value),
+                ty: vint.ty,
+            },
             // Already in WHNF
-            vint @ ValueInternal::ValueF(WHNF, _)
-            | vint @ ValueInternal::ValueF(NF, _) => vint,
+            WHNF | NF => vint,
         })
     }
-
     fn normalize_nf(&mut self) {
-        match self {
-            ValueInternal::ValueF(Unevaled, _) => {
+        match self.form {
+            Unevaled => {
                 self.normalize_whnf();
                 self.normalize_nf();
             }
-            ValueInternal::ValueF(f @ WHNF, v) => {
-                v.normalize_mut();
-                *f = NF;
+            WHNF => {
+                self.value.normalize_mut();
+                self.form = NF;
             }
             // Already in NF
-            ValueInternal::ValueF(NF, _) => {}
+            NF => {}
         }
     }
 
-    // Always use normalize_whnf before
+    /// Always use normalize_whnf before
     fn as_whnf(&self) -> &ValueF {
-        match self {
-            ValueInternal::ValueF(Unevaled, _) => unreachable!(),
-            ValueInternal::ValueF(_, v) => v,
+        match self.form {
+            Unevaled => unreachable!(),
+            _ => &self.value,
         }
     }
-
-    // Always use normalize_nf before
+    /// Always use normalize_nf before
     fn as_nf(&self) -> &ValueF {
-        match self {
-            ValueInternal::ValueF(Unevaled, _)
-            | ValueInternal::ValueF(WHNF, _) => unreachable!(),
-            ValueInternal::ValueF(NF, v) => v,
+        match self.form {
+            Unevaled | WHNF => unreachable!(),
+            NF => &self.value,
         }
     }
-}
 
-impl TypedValueInternal {
-    fn into_value(self) -> Value {
-        Value(Rc::new(RefCell::new(self)))
-    }
-    fn as_internal(&self) -> &ValueInternal {
-        &self.internal
-    }
-    fn as_internal_mut(&mut self) -> &mut ValueInternal {
-        &mut self.internal
-    }
-
-    fn get_type(&self) -> Result<Type, TypeError> {
-        match &self.typ {
-            Some(t) => Ok(t.clone()),
+    fn get_type(&self) -> Result<&Type, TypeError> {
+        match &self.ty {
+            Some(t) => Ok(t),
             None => Err(TypeError::new(
                 &TypecheckContext::new(),
                 TypeMessage::Untyped,
@@ -131,70 +109,80 @@ impl TypedValueInternal {
 
 impl Value {
     pub(crate) fn from_valuef(v: ValueF) -> Value {
-        ValueInternal::ValueF(Unevaled, v).into_value(None)
+        ValueInternal {
+            form: Unevaled,
+            value: v,
+            ty: None,
+        }
+        .into_value()
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Value {
-        ValueInternal::ValueF(Unevaled, v).into_value(Some(t))
+        ValueInternal {
+            form: Unevaled,
+            value: v,
+            ty: Some(t),
+        }
+        .into_value()
     }
     pub(crate) fn from_partial_expr(e: ExprF<Value, Normalized>) -> Value {
         Value::from_valuef(ValueF::PartialExpr(e))
     }
+    // TODO: avoid using this function
     pub(crate) fn with_type(self, t: Type) -> Value {
-        self.as_internal().clone().into_value(Some(t))
+        let vint = self.as_internal();
+        ValueInternal {
+            form: vint.form,
+            value: vint.value.clone(),
+            ty: Some(t),
+        }
+        .into_value()
     }
 
     /// Mutates the contents. If no one else shares this thunk,
     /// mutates directly, thus avoiding a RefCell lock.
-    fn mutate_internal(&mut self, f: impl FnOnce(&mut TypedValueInternal)) {
+    fn mutate_internal(&mut self, f: impl FnOnce(&mut ValueInternal)) {
         match Rc::get_mut(&mut self.0) {
             // Mutate directly if sole owner
             Some(refcell) => f(RefCell::get_mut(refcell)),
             // Otherwise mutate through the refcell
-            None => f(&mut self.as_tinternal_mut()),
+            None => f(&mut self.as_internal_mut()),
         }
     }
 
     /// Normalizes contents to normal form; faster than `normalize_nf` if
     /// no one else shares this thunk.
     pub(crate) fn normalize_mut(&mut self) {
-        self.mutate_internal(|i| i.as_internal_mut().normalize_nf())
+        self.mutate_internal(|vint| vint.normalize_nf())
     }
 
-    fn as_tinternal(&self) -> Ref<TypedValueInternal> {
-        self.0.borrow()
-    }
-    fn as_tinternal_mut(&mut self) -> RefMut<TypedValueInternal> {
-        self.0.borrow_mut()
-    }
     fn as_internal(&self) -> Ref<ValueInternal> {
-        Ref::map(self.as_tinternal(), TypedValueInternal::as_internal)
+        self.0.borrow()
     }
     fn as_internal_mut(&self) -> RefMut<ValueInternal> {
-        RefMut::map(self.0.borrow_mut(), TypedValueInternal::as_internal_mut)
+        self.0.borrow_mut()
     }
 
     fn do_normalize_whnf(&self) {
         let borrow = self.as_internal();
-        match &*borrow {
-            ValueInternal::ValueF(Unevaled, _) => {
+        match borrow.form {
+            Unevaled => {
                 drop(borrow);
                 self.as_internal_mut().normalize_whnf();
             }
             // Already at least in WHNF
-            ValueInternal::ValueF(WHNF, _) | ValueInternal::ValueF(NF, _) => {}
+            WHNF | NF => {}
         }
     }
 
     fn do_normalize_nf(&self) {
         let borrow = self.as_internal();
-        match &*borrow {
-            ValueInternal::ValueF(Unevaled, _)
-            | ValueInternal::ValueF(WHNF, _) => {
+        match borrow.form {
+            Unevaled | WHNF => {
                 drop(borrow);
                 self.as_internal_mut().normalize_nf();
             }
             // Already in NF
-            ValueInternal::ValueF(NF, _) => {}
+            NF => {}
         }
     }
 
@@ -240,7 +228,7 @@ impl Value {
     }
 
     pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
-        Ok(Cow::Owned(self.as_tinternal().get_type()?))
+        Ok(Cow::Owned(self.as_internal().get_type()?.clone()))
     }
 }
 
@@ -330,10 +318,10 @@ impl Shift for Value {
 
 impl Shift for ValueInternal {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(match self {
-            ValueInternal::ValueF(f, v) => {
-                ValueInternal::ValueF(*f, v.shift(delta, var)?)
-            }
+        Some(ValueInternal {
+            form: self.form,
+            value: self.value.shift(delta, var)?,
+            ty: self.ty.shift(delta, var)?,
         })
     }
 }
@@ -344,15 +332,6 @@ impl Shift for TypedValue {
     }
 }
 
-impl Shift for TypedValueInternal {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(TypedValueInternal {
-            internal: self.internal.shift(delta, var)?,
-            typ: self.typ.shift(delta, var)?,
-        })
-    }
-}
-
 impl Subst<Typed> for Value {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
         Value(self.0.subst_shift(var, val))
@@ -361,20 +340,11 @@ impl Subst<Typed> for Value {
 
 impl Subst<Typed> for ValueInternal {
     fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        match self {
-            ValueInternal::ValueF(_, v) => {
-                // The resulting value may not stay in wnhf after substitution
-                ValueInternal::ValueF(Unevaled, v.subst_shift(var, val))
-            }
-        }
-    }
-}
-
-impl Subst<Typed> for TypedValueInternal {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
-        TypedValueInternal {
-            internal: self.internal.subst_shift(var, val),
-            typ: self.typ.subst_shift(var, val),
+        ValueInternal {
+            // The resulting value may not stay in wnhf after substitution
+            form: Unevaled,
+            value: self.value.subst_shift(var, val),
+            ty: self.ty.subst_shift(var, val),
         }
     }
 }
@@ -401,11 +371,9 @@ impl std::cmp::Eq for TypedValue {}
 
 impl std::fmt::Debug for Value {
     fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let b: &ValueInternal = &self.as_internal();
-        match b {
-            ValueInternal::ValueF(f, v) => {
-                fmt.debug_tuple(&format!("Value@{:?}", f)).field(v).finish()
-            }
-        }
+        let vint: &ValueInternal = &self.as_internal();
+        fmt.debug_tuple(&format!("Value@{:?}", &vint.form))
+            .field(&vint.value)
+            .finish()
     }
 }
-- 
cgit v1.3.1


From 29016b78736dca857e4e7f7c4dc68ed5e30c28bb Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 19 Aug 2019 12:25:09 +0200
Subject: s/to_valuef/to_whnf/ and avoid cloning ValueFs when possible

---
 dhall/src/core/value.rs      |  38 ++++-----
 dhall/src/core/valuef.rs     |   7 +-
 dhall/src/error/mod.rs       |  20 ++---
 dhall/src/phase/mod.rs       |  15 ++--
 dhall/src/phase/normalize.rs |  94 ++++++++++----------
 dhall/src/phase/typecheck.rs | 198 ++++++++++++++++++++-----------------------
 dhall/src/tests.rs           |   2 +-
 7 files changed, 182 insertions(+), 192 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index ef43e3e..213a2bd 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -193,23 +193,17 @@ impl Value {
         Ref::map(self.as_internal(), ValueInternal::as_nf)
     }
 
-    /// WARNING: avoid normalizing any thunk while holding on to this ref
-    /// or you could run into BorrowMut panics
-    /// TODO: deprecated because of misleading name
-    pub(crate) fn as_valuef(&self) -> Ref<ValueF> {
-        self.as_whnf()
-    }
-
-    /// WARNING: avoid normalizing any thunk while holding on to this ref
-    /// or you could run into BorrowMut panics
+    /// This is what you want if you want to pattern-match on the value.
+    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
+    /// panics.
     pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
         self.do_normalize_whnf();
         Ref::map(self.as_internal(), ValueInternal::as_whnf)
     }
 
-    /// TODO: deprecated because of misleading name
-    pub(crate) fn to_valuef(&self) -> ValueF {
-        self.as_valuef().clone()
+    /// TODO: cloning a valuef can often be avoided
+    pub(crate) fn to_whnf(&self) -> ValueF {
+        self.as_whnf().clone()
     }
 
     pub(crate) fn normalize_to_expr_maybe_alpha(
@@ -275,14 +269,19 @@ impl TypedValue {
         TypedValue(Value::from_valuef_and_type(v, t))
     }
 
-    pub(crate) fn to_valuef(&self) -> ValueF {
-        self.0.to_valuef()
+    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
+    /// panics.
+    pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
+        self.0.as_whnf()
+    }
+    pub(crate) fn to_whnf(&self) -> ValueF {
+        self.0.to_whnf()
     }
     pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
-        self.to_valuef().normalize_to_expr()
+        self.as_whnf().normalize_to_expr()
     }
     pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
-        self.to_valuef().normalize_to_expr_maybe_alpha(true)
+        self.as_whnf().normalize_to_expr_maybe_alpha(true)
     }
     pub(crate) fn to_value(&self) -> Value {
         self.0.clone()
@@ -294,8 +293,7 @@ impl TypedValue {
         Typed::from_typedvalue(self)
     }
     pub(crate) fn as_const(&self) -> Option<Const> {
-        // TODO: avoid clone
-        match &self.to_valuef() {
+        match &*self.as_whnf() {
             ValueF::Const(c) => Some(*c),
             _ => None,
         }
@@ -357,14 +355,14 @@ impl Subst<Typed> for TypedValue {
 
 impl std::cmp::PartialEq for Value {
     fn eq(&self, other: &Self) -> bool {
-        *self.as_valuef() == *other.as_valuef()
+        *self.as_whnf() == *other.as_whnf()
     }
 }
 impl std::cmp::Eq for Value {}
 
 impl std::cmp::PartialEq for TypedValue {
     fn eq(&self, other: &Self) -> bool {
-        self.to_valuef() == other.to_valuef()
+        &*self.as_whnf() == &*other.as_whnf()
     }
 }
 impl std::cmp::Eq for TypedValue {}
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 9e6e8c8..0ba1d59 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -12,8 +12,9 @@ use crate::phase::{Normalized, Typed};
 
 /// A semantic value. Subexpressions are Values, which are partially evaluated expressions that are
 /// normalized on-demand.
-/// Equality is up to alpha-equivalence (renaming of bound variables) and beta-equivalence
-/// (normalization). Equality will normalize as needed.
+/// If you compare for equality two `ValueF`s in WHNF, then equality will be up to
+/// alpha-equivalence (renaming of bound variables) and beta-equivalence (normalization). It will
+/// recursively normalize as needed.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ValueF {
     /// Closures
@@ -348,7 +349,7 @@ impl Subst<Typed> for ValueF {
                 t.subst_shift(var, val),
                 e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
             ),
-            ValueF::Var(v) if v == var => val.to_valuef(),
+            ValueF::Var(v) if v == var => val.to_whnf(),
             ValueF::Var(v) => ValueF::Var(v.shift(-1, var).unwrap()),
             ValueF::Const(c) => ValueF::Const(*c),
             ValueF::BoolLit(b) => ValueF::BoolLit(*b),
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 8f6ff51..34a89c0 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -4,7 +4,7 @@ use dhall_syntax::{BinOp, Import, Label, ParseError, V};
 
 use crate::core::context::TypecheckContext;
 use crate::phase::resolve::ImportStack;
-use crate::phase::{Normalized, NormalizedSubExpr, Type, Typed};
+use crate::phase::{NormalizedSubExpr, Type, Typed};
 
 pub type Result<T> = std::result::Result<T, Error>;
 
@@ -48,24 +48,24 @@ pub struct TypeError {
 #[derive(Debug)]
 pub(crate) enum TypeMessage {
     UnboundVariable(V<Label>),
-    InvalidInputType(Normalized),
-    InvalidOutputType(Normalized),
+    InvalidInputType(Typed),
+    InvalidOutputType(Typed),
     NotAFunction(Typed),
-    TypeMismatch(Typed, Normalized, Typed),
-    AnnotMismatch(Typed, Normalized),
+    TypeMismatch(Typed, Typed, Typed),
+    AnnotMismatch(Typed, Typed),
     Untyped,
     FieldCollision(Label),
-    InvalidListElement(usize, Normalized, Typed),
-    InvalidListType(Normalized),
-    InvalidOptionalType(Normalized),
+    InvalidListElement(usize, Typed, Typed),
+    InvalidListType(Typed),
+    InvalidOptionalType(Typed),
     InvalidPredicate(Typed),
     IfBranchMismatch(Typed, Typed),
     IfBranchMustBeTerm(bool, Typed),
     InvalidFieldType(Label, Type),
-    NotARecord(Label, Normalized),
+    NotARecord(Label, Typed),
     MustCombineRecord(Typed),
     MissingRecordField(Label, Typed),
-    MissingUnionField(Label, Normalized),
+    MissingUnionField(Label, Typed),
     BinOpTypeMismatch(BinOp, Typed),
     InvalidTextInterpolation(Typed),
     Merge1ArgMustBeRecord(Typed),
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index c18f976..a38e9d3 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -1,4 +1,5 @@
 use std::borrow::Cow;
+use std::cell::Ref;
 use std::fmt::Display;
 use std::path::Path;
 
@@ -111,8 +112,13 @@ impl Typed {
         Typed::from_const(Const::Type)
     }
 
-    pub(crate) fn to_valuef(&self) -> ValueF {
-        self.0.to_valuef()
+    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
+    /// panics.
+    pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
+        self.0.as_whnf()
+    }
+    pub(crate) fn to_whnf(&self) -> ValueF {
+        self.0.to_whnf()
     }
     pub fn to_expr(&self) -> NormalizedSubExpr {
         self.0.to_expr()
@@ -134,9 +140,6 @@ impl Typed {
     pub(crate) fn into_typedvalue(self) -> TypedValue {
         self.0
     }
-    pub(crate) fn to_normalized(&self) -> Normalized {
-        self.clone().normalize()
-    }
     pub(crate) fn as_const(&self) -> Option<Const> {
         self.0.as_const()
     }
@@ -229,7 +232,7 @@ impl std::hash::Hash for Normalized {
 impl Eq for Typed {}
 impl PartialEq for Typed {
     fn eq(&self, other: &Self) -> bool {
-        self.to_valuef() == other.to_valuef()
+        self.0 == other.0
     }
 }
 
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 6c65e43..785a75f 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -68,23 +68,23 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             r,
             EmptyOptionalLit(TypedValue::from_value_simple_type(t.clone())),
         )),
-        (NaturalIsZero, [n, r..]) => match &*n.as_valuef() {
+        (NaturalIsZero, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
             _ => Err(()),
         },
-        (NaturalEven, [n, r..]) => match &*n.as_valuef() {
+        (NaturalEven, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0))),
             _ => Err(()),
         },
-        (NaturalOdd, [n, r..]) => match &*n.as_valuef() {
+        (NaturalOdd, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0))),
             _ => Err(()),
         },
-        (NaturalToInteger, [n, r..]) => match &*n.as_valuef() {
+        (NaturalToInteger, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((r, IntegerLit(*n as isize))),
             _ => Err(()),
         },
-        (NaturalShow, [n, r..]) => match &*n.as_valuef() {
+        (NaturalShow, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((
                 r,
                 TextLit(vec![InterpolatedTextContents::Text(n.to_string())]),
@@ -92,7 +92,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             _ => Err(()),
         },
         (NaturalSubtract, [a, b, r..]) => {
-            match (&*a.as_valuef(), &*b.as_valuef()) {
+            match (&*a.as_whnf(), &*b.as_whnf()) {
                 (NaturalLit(a), NaturalLit(b)) => {
                     Ok((r, NaturalLit(if b > a { b - a } else { 0 })))
                 }
@@ -102,7 +102,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 _ => Err(()),
             }
         }
-        (IntegerShow, [n, r..]) => match &*n.as_valuef() {
+        (IntegerShow, [n, r..]) => match &*n.as_whnf() {
             IntegerLit(n) => {
                 let s = if *n < 0 {
                     n.to_string()
@@ -113,18 +113,18 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
             _ => Err(()),
         },
-        (IntegerToDouble, [n, r..]) => match &*n.as_valuef() {
+        (IntegerToDouble, [n, r..]) => match &*n.as_whnf() {
             IntegerLit(n) => Ok((r, DoubleLit(NaiveDouble::from(*n as f64)))),
             _ => Err(()),
         },
-        (DoubleShow, [n, r..]) => match &*n.as_valuef() {
+        (DoubleShow, [n, r..]) => match &*n.as_whnf() {
             DoubleLit(n) => Ok((
                 r,
                 TextLit(vec![InterpolatedTextContents::Text(n.to_string())]),
             )),
             _ => Err(()),
         },
-        (TextShow, [v, r..]) => match &*v.as_valuef() {
+        (TextShow, [v, r..]) => match &*v.as_whnf() {
             TextLit(elts) => {
                 match elts.as_slice() {
                     // Empty string literal.
@@ -158,33 +158,33 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
             _ => Err(()),
         },
-        (ListLength, [_, l, r..]) => match &*l.as_valuef() {
+        (ListLength, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(_) => Ok((r, NaturalLit(0))),
             NEListLit(xs) => Ok((r, NaturalLit(xs.len()))),
             _ => Err(()),
         },
-        (ListHead, [_, l, r..]) => match &*l.as_valuef() {
+        (ListHead, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))),
             NEListLit(xs) => {
                 Ok((r, NEOptionalLit(xs.iter().next().unwrap().clone())))
             }
             _ => Err(()),
         },
-        (ListLast, [_, l, r..]) => match &*l.as_valuef() {
+        (ListLast, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))),
             NEListLit(xs) => {
                 Ok((r, NEOptionalLit(xs.iter().rev().next().unwrap().clone())))
             }
             _ => Err(()),
         },
-        (ListReverse, [_, l, r..]) => match &*l.as_valuef() {
+        (ListReverse, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(n) => Ok((r, EmptyListLit(n.clone()))),
             NEListLit(xs) => {
                 Ok((r, NEListLit(xs.iter().rev().cloned().collect())))
             }
             _ => Err(()),
         },
-        (ListIndexed, [_, l, r..]) => match &*l.as_valuef() {
+        (ListIndexed, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(t) => {
                 let mut kts = HashMap::new();
                 kts.insert(
@@ -210,11 +210,11 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
             _ => Err(()),
         },
-        (ListBuild, [t, f, r..]) => match &*f.as_valuef() {
+        (ListBuild, [t, f, r..]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(ListFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].to_valuef()))
+                    Ok((r, args[1].to_whnf()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -237,8 +237,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     )),
             )),
         },
-        (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_valuef() {
-            EmptyListLit(_) => Ok((r, nil.to_valuef())),
+        (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() {
+            EmptyListLit(_) => Ok((r, nil.to_whnf())),
             NEListLit(xs) => {
                 let mut v = nil.clone();
                 for x in xs.iter().rev() {
@@ -248,15 +248,15 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                         .app_value(v)
                         .into_value();
                 }
-                Ok((r, v.to_valuef()))
+                Ok((r, v.to_whnf()))
             }
             _ => Err(()),
         },
-        (OptionalBuild, [t, f, r..]) => match &*f.as_valuef() {
+        (OptionalBuild, [t, f, r..]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(OptionalFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].to_valuef()))
+                    Ok((r, args[1].to_whnf()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -273,18 +273,16 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 )),
             )),
         },
-        (OptionalFold, [_, v, _, just, nothing, r..]) => {
-            match &*v.as_valuef() {
-                EmptyOptionalLit(_) => Ok((r, nothing.to_valuef())),
-                NEOptionalLit(x) => Ok((r, just.app_value(x.clone()))),
-                _ => Err(()),
-            }
-        }
-        (NaturalBuild, [f, r..]) => match &*f.as_valuef() {
+        (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
+            EmptyOptionalLit(_) => Ok((r, nothing.to_whnf())),
+            NEOptionalLit(x) => Ok((r, just.app_value(x.clone()))),
+            _ => Err(()),
+        },
+        (NaturalBuild, [f, r..]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(NaturalFold, args) => {
                 if !args.is_empty() {
-                    Ok((r, args[0].to_valuef()))
+                    Ok((r, args[0].to_whnf()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -297,8 +295,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     .app_valuef(NaturalLit(0)),
             )),
         },
-        (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_valuef() {
-            NaturalLit(0) => Ok((r, zero.to_valuef())),
+        (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() {
+            NaturalLit(0) => Ok((r, zero.to_whnf())),
             NaturalLit(n) => {
                 let fold = ValueF::from_builtin(NaturalFold)
                     .app(NaturalLit(n - 1))
@@ -326,11 +324,11 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
 pub(crate) fn apply_any(f: Value, a: Value) -> ValueF {
     let fallback = |f: Value, a: Value| ValueF::PartialExpr(ExprF::App(f, a));
 
-    let f_borrow = f.as_valuef();
+    let f_borrow = f.as_whnf();
     match &*f_borrow {
         ValueF::Lam(x, _, e) => {
             let val = Typed::from_value_untyped(a);
-            e.subst_shift(&x.into(), &val).to_valuef()
+            e.subst_shift(&x.into(), &val).to_whnf()
         }
         ValueF::AppliedBuiltin(b, args) => {
             use std::iter::once;
@@ -362,7 +360,7 @@ pub(crate) fn squash_textlit(
             match contents {
                 Text(s) => crnt_str.push_str(&s),
                 Expr(e) => {
-                    let e_borrow = e.as_valuef();
+                    let e_borrow = e.as_whnf();
                     match &*e_borrow {
                         ValueF::TextLit(elts2) => {
                             inner(elts2.iter().cloned(), crnt_str, ret)
@@ -520,8 +518,8 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
         BoolLit, EmptyListLit, NEListLit, NaturalLit, RecordLit, RecordType,
         TextLit,
     };
-    let x_borrow = x.as_valuef();
-    let y_borrow = y.as_valuef();
+    let x_borrow = x.as_whnf();
+    let y_borrow = y.as_whnf();
     Some(match (o, &*x_borrow, &*y_borrow) {
         (BoolAnd, BoolLit(true), _) => Ret::ValueRef(y),
         (BoolAnd, _, BoolLit(true)) => Ret::ValueRef(x),
@@ -678,7 +676,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         ExprF::SomeLit(e) => Ret::ValueF(NEOptionalLit(e)),
         ExprF::EmptyListLit(ref t) => {
             // Check if the type is of the form `List x`
-            let t_borrow = t.as_valuef();
+            let t_borrow = t.as_whnf();
             match &*t_borrow {
                 AppliedBuiltin(Builtin::List, args) if args.len() == 1 => {
                     Ret::ValueF(EmptyListLit(
@@ -718,13 +716,13 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
             }
         }
         ExprF::BoolIf(ref b, ref e1, ref e2) => {
-            let b_borrow = b.as_valuef();
+            let b_borrow = b.as_whnf();
             match &*b_borrow {
                 BoolLit(true) => Ret::ValueRef(e1),
                 BoolLit(false) => Ret::ValueRef(e2),
                 _ => {
-                    let e1_borrow = e1.as_valuef();
-                    let e2_borrow = e2.as_valuef();
+                    let e1_borrow = e1.as_whnf();
+                    let e2_borrow = e2.as_whnf();
                     match (&*e1_borrow, &*e2_borrow) {
                         // Simplify `if b then True else False`
                         (BoolLit(true), BoolLit(false)) => Ret::ValueRef(b),
@@ -748,7 +746,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
             Ret::ValueF(RecordLit(HashMap::new()))
         }
         ExprF::Projection(ref v, ref ls) => {
-            let v_borrow = v.as_valuef();
+            let v_borrow = v.as_whnf();
             match &*v_borrow {
                 RecordLit(kvs) => Ret::ValueF(RecordLit(
                     ls.iter()
@@ -764,7 +762,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
             }
         }
         ExprF::Field(ref v, ref l) => {
-            let v_borrow = v.as_valuef();
+            let v_borrow = v.as_whnf();
             match &*v_borrow {
                 RecordLit(kvs) => match kvs.get(l) {
                     Some(r) => Ret::Value(r.clone()),
@@ -784,8 +782,8 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         }
 
         ExprF::Merge(ref handlers, ref variant, _) => {
-            let handlers_borrow = handlers.as_valuef();
-            let variant_borrow = variant.as_valuef();
+            let handlers_borrow = handlers.as_whnf();
+            let variant_borrow = variant.as_whnf();
             match (&*handlers_borrow, &*variant_borrow) {
                 (RecordLit(kvs), UnionConstructor(l, _)) => match kvs.get(l) {
                     Some(h) => Ret::Value(h.clone()),
@@ -814,8 +812,8 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
 
     match ret {
         Ret::ValueF(v) => v,
-        Ret::Value(th) => th.to_valuef(),
-        Ret::ValueRef(th) => th.to_valuef(),
+        Ret::Value(th) => th.as_whnf().clone(),
+        Ret::ValueRef(th) => th.as_whnf().clone(),
         Ret::Expr(expr) => ValueF::PartialExpr(expr),
     }
 }
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 4154afe..c303ada 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -22,12 +22,7 @@ fn tck_pi_type(
 
     let ka = match tx.get_type()?.as_const() {
         Some(k) => k,
-        _ => {
-            return Err(TypeError::new(
-                ctx,
-                InvalidInputType(tx.to_normalized()),
-            ))
-        }
+        _ => return Err(TypeError::new(ctx, InvalidInputType(tx))),
     };
 
     let kb = match te.get_type()?.as_const() {
@@ -35,7 +30,7 @@ fn tck_pi_type(
         _ => {
             return Err(TypeError::new(
                 &ctx2,
-                InvalidOutputType(te.get_type()?.to_normalized()),
+                InvalidOutputType(te.get_type()?.into_owned()),
             ))
         }
     };
@@ -415,18 +410,14 @@ fn type_last_layer(
         }
         App(f, a) => {
             let tf = f.get_type()?;
-            let (x, tx, tb) = match &tf.to_valuef() {
+            let (x, tx, tb) = match &*tf.as_whnf() {
                 ValueF::Pi(x, tx, tb) => {
                     (x.clone(), tx.to_type(), tb.to_type())
                 }
                 _ => return Err(mkerr(NotAFunction(f.clone()))),
             };
             if a.get_type()?.as_ref() != &tx {
-                return Err(mkerr(TypeMismatch(
-                    f.clone(),
-                    tx.to_normalized(),
-                    a.clone(),
-                )));
+                return Err(mkerr(TypeMismatch(f.clone(), tx, a.clone())));
             }
 
             Ok(RetTypeOnly(tb.subst_shift(&x.into(), &a)))
@@ -434,13 +425,13 @@ fn type_last_layer(
         Annot(x, t) => {
             let t = t.to_type();
             if &t != x.get_type()?.as_ref() {
-                return Err(mkerr(AnnotMismatch(x.clone(), t.to_normalized())));
+                return Err(mkerr(AnnotMismatch(x.clone(), t)));
             }
             Ok(RetTypeOnly(x.get_type()?.into_owned()))
         }
         Assert(t) => {
-            match t.to_valuef() {
-                ValueF::Equivalence(ref x, ref y) if x == y => {}
+            match &*t.as_whnf() {
+                ValueF::Equivalence(x, y) if x == y => {}
                 ValueF::Equivalence(x, y) => {
                     return Err(mkerr(AssertMismatch(
                         x.to_typed(),
@@ -472,14 +463,11 @@ fn type_last_layer(
         }
         EmptyListLit(t) => {
             let t = t.to_type();
-            match &t.to_valuef() {
+            match &*t.as_whnf() {
                 ValueF::AppliedBuiltin(dhall_syntax::Builtin::List, args)
                     if args.len() == 1 => {}
                 _ => {
-                    return Err(TypeError::new(
-                        ctx,
-                        InvalidListType(t.to_normalized()),
-                    ))
+                    return Err(TypeError::new(ctx, InvalidListType(t.clone())))
                 }
             }
             Ok(RetTypeOnly(t))
@@ -491,7 +479,7 @@ fn type_last_layer(
                 if x.get_type()? != y.get_type()? {
                     return Err(mkerr(InvalidListElement(
                         i,
-                        x.get_type()?.to_normalized(),
+                        x.get_type()?.into_owned(),
                         y.clone(),
                     )));
                 }
@@ -500,14 +488,14 @@ fn type_last_layer(
             if t.get_type()?.as_const() != Some(Type) {
                 return Err(TypeError::new(
                     ctx,
-                    InvalidListType(t.to_normalized()),
+                    InvalidListType(t.into_owned()),
                 ));
             }
 
             Ok(RetTypeOnly(
                 Typed::from_value_and_type(
                     ValueF::from_builtin(dhall_syntax::Builtin::List)
-                        .app(t.to_valuef())
+                        .app_value(t.to_value())
                         .into_value(),
                     Typed::from_const(Type),
                 )
@@ -517,16 +505,13 @@ fn type_last_layer(
         SomeLit(x) => {
             let t = x.get_type()?.into_owned();
             if t.get_type()?.as_const() != Some(Type) {
-                return Err(TypeError::new(
-                    ctx,
-                    InvalidOptionalType(t.to_normalized()),
-                ));
+                return Err(TypeError::new(ctx, InvalidOptionalType(t)));
             }
 
             Ok(RetTypeOnly(
                 Typed::from_value_and_type(
                     ValueF::from_builtin(dhall_syntax::Builtin::Optional)
-                        .app(t.to_valuef())
+                        .app_value(t.to_value())
                         .into_value(),
                     Typed::from_const(Type).into_type(),
                 )
@@ -551,7 +536,7 @@ fn type_last_layer(
             .into_type(),
         )),
         Field(r, x) => {
-            match &r.get_type()?.to_valuef() {
+            match &*r.get_type()?.as_whnf() {
                 ValueF::RecordType(kts) => match kts.get(&x) {
                     Some(tth) => {
                         Ok(RetTypeOnly(tth.to_type()))
@@ -561,8 +546,7 @@ fn type_last_layer(
                 },
                 // TODO: branch here only when r.get_type() is a Const
                 _ => {
-                    let r = r.to_type();
-                    match &r.to_valuef() {
+                    match &*r.as_whnf() {
                         ValueF::UnionType(kts) => match kts.get(&x) {
                             // Constructor has type T -> < x: T, ... >
                             Some(Some(t)) => {
@@ -581,21 +565,21 @@ fn type_last_layer(
                             None => {
                                 Err(mkerr(MissingUnionField(
                                     x.clone(),
-                                    r.to_normalized(),
+                                    r.clone(),
                                 )))
                             },
                         },
                         _ => {
                             Err(mkerr(NotARecord(
                                 x.clone(),
-                                r.to_normalized()
+                                r.clone()
                             )))
                         },
                     }
                 }
                 // _ => Err(mkerr(NotARecord(
                 //     x,
-                //     r.to_type()?.to_normalized(),
+                //     r.to_type()?,
                 // ))),
             }
         }
@@ -633,20 +617,22 @@ fn type_last_layer(
             }
 
             // Extract the LHS record type
-            let kts_x = match l_type.to_valuef() {
+            let l_type_borrow = l_type.as_whnf();
+            let kts_x = match &*l_type_borrow {
                 ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(l.clone()))),
             };
 
             // Extract the RHS record type
-            let kts_y = match r_type.to_valuef() {
+            let r_type_borrow = r_type.as_whnf();
+            let kts_y = match &*r_type_borrow {
                 ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(r.clone()))),
             };
 
             // Union the two records, prefering
             // the values found in the RHS.
-            let kts = merge_maps(&kts_x, &kts_y, |_, r_t| r_t.clone());
+            let kts = merge_maps(kts_x, kts_y, |_, r_t| r_t.clone());
 
             // Construct the final record type from the union
             Ok(RetTypeOnly(
@@ -662,8 +648,8 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: HashMap<Label, TypedValue>,
-                kts_r: HashMap<Label, TypedValue>,
+                kts_l: &HashMap<Label, TypedValue>,
+                kts_r: &HashMap<Label, TypedValue>,
             ) -> Result<Typed, TypeError> {
                 use crate::phase::normalize::outer_join;
 
@@ -674,7 +660,7 @@ fn type_last_layer(
                                inner_l: &TypedValue,
                                inner_r: &TypedValue|
                  -> Result<Typed, TypeError> {
-                    match (inner_l.to_valuef(), inner_r.to_valuef()) {
+                    match (&*inner_l.as_whnf(), &*inner_r.as_whnf()) {
                         (
                             ValueF::RecordType(inner_l_kvs),
                             ValueF::RecordType(inner_r_kvs),
@@ -690,11 +676,9 @@ fn type_last_layer(
                 let kts: HashMap<Label, Result<Typed, TypeError>> = outer_join(
                     |l| Ok(l.to_type()),
                     |r| Ok(r.to_type()),
-                    |k: &Label, l: &TypedValue, r: &TypedValue| {
-                        combine(k, l, r)
-                    },
-                    &kts_l,
-                    &kts_r,
+                    combine,
+                    kts_l,
+                    kts_r,
                 );
 
                 Ok(tck_record_type(
@@ -717,13 +701,15 @@ fn type_last_layer(
             }
 
             // Extract the LHS record type
-            let kts_x = match l_type.to_valuef() {
+            let l_type_borrow = l_type.as_whnf();
+            let kts_x = match &*l_type_borrow {
                 ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(l.clone()))),
             };
 
             // Extract the RHS record type
-            let kts_y = match r_type.to_valuef() {
+            let r_type_borrow = r_type.as_whnf();
+            let kts_y = match &*r_type_borrow {
                 ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(MustCombineRecord(r.clone()))),
             };
@@ -735,8 +721,8 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: HashMap<Label, TypedValue>,
-                kts_r: HashMap<Label, TypedValue>,
+                kts_l: &HashMap<Label, TypedValue>,
+                kts_r: &HashMap<Label, TypedValue>,
             ) -> Result<Typed, TypeError> {
                 use crate::phase::normalize::intersection_with_key;
 
@@ -747,7 +733,7 @@ fn type_last_layer(
                                kts_l_inner: &TypedValue,
                                kts_r_inner: &TypedValue|
                  -> Result<Typed, TypeError> {
-                    match (kts_l_inner.to_valuef(), kts_r_inner.to_valuef()) {
+                    match (&*kts_l_inner.as_whnf(), &*kts_r_inner.as_whnf()) {
                         (
                             ValueF::RecordType(kvs_l_inner),
                             ValueF::RecordType(kvs_r_inner),
@@ -760,13 +746,7 @@ fn type_last_layer(
                     }
                 };
 
-                let kts = intersection_with_key(
-                    |k: &Label, l: &TypedValue, r: &TypedValue| {
-                        combine(k, l, r)
-                    },
-                    &kts_l,
-                    &kts_r,
-                );
+                let kts = intersection_with_key(combine, kts_l, kts_r);
 
                 Ok(tck_record_type(
                     ctx,
@@ -776,8 +756,8 @@ fn type_last_layer(
             };
 
             // Extract the Const of the LHS
-            let k_l = match l.get_type()?.to_valuef() {
-                ValueF::Const(k) => k,
+            let k_l = match l.get_type()?.as_const() {
+                Some(k) => k,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
                         l.clone(),
@@ -786,8 +766,8 @@ fn type_last_layer(
             };
 
             // Extract the Const of the RHS
-            let k_r = match r.get_type()?.to_valuef() {
-                ValueF::Const(k) => k,
+            let k_r = match r.get_type()?.as_const() {
+                Some(k) => k,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
                         r.clone(),
@@ -808,7 +788,8 @@ fn type_last_layer(
             };
 
             // Extract the LHS record type
-            let kts_x = match l.to_valuef() {
+            let borrow_l = l.as_whnf();
+            let kts_x = match &*borrow_l {
                 ValueF::RecordType(kts) => kts,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
@@ -818,7 +799,8 @@ fn type_last_layer(
             };
 
             // Extract the RHS record type
-            let kts_y = match r.to_valuef() {
+            let borrow_r = r.as_whnf();
+            let kts_y = match &*borrow_r {
                 ValueF::RecordType(kts) => kts,
                 _ => {
                     return Err(mkerr(RecordTypeMergeRequiresRecordType(
@@ -833,7 +815,7 @@ fn type_last_layer(
                 .and(Ok(RetTypeOnly(Typed::from_const(k))))
         }
         BinOp(o @ ListAppend, l, r) => {
-            match l.get_type()?.to_valuef() {
+            match &*l.get_type()?.as_whnf() {
                 ValueF::AppliedBuiltin(List, _) => {}
                 _ => return Err(mkerr(BinOpTypeMismatch(*o, l.clone()))),
             }
@@ -895,56 +877,63 @@ fn type_last_layer(
             Ok(RetTypeOnly(t))
         }
         Merge(record, union, type_annot) => {
-            let handlers = match record.get_type()?.to_valuef() {
+            let record_type = record.get_type()?;
+            let record_borrow = record_type.as_whnf();
+            let handlers = match &*record_borrow {
                 ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(Merge1ArgMustBeRecord(record.clone()))),
             };
 
-            let variants = match union.get_type()?.to_valuef() {
+            let union_type = union.get_type()?;
+            let union_borrow = union_type.as_whnf();
+            let variants = match &*union_borrow {
                 ValueF::UnionType(kts) => kts,
                 _ => return Err(mkerr(Merge2ArgMustBeUnion(union.clone()))),
             };
 
             let mut inferred_type = None;
-            for (x, handler) in handlers.iter() {
-                let handler_return_type = match variants.get(x) {
-                    // Union alternative with type
-                    Some(Some(variant_type)) => {
-                        let variant_type = variant_type.to_type();
-                        let handler_type = handler.to_type();
-                        let (x, tx, tb) = match &handler_type.to_valuef() {
-                            ValueF::Pi(x, tx, tb) => {
-                                (x.clone(), tx.to_type(), tb.to_type())
+            for (x, handler) in handlers {
+                let handler_return_type =
+                    match variants.get(x) {
+                        // Union alternative with type
+                        Some(Some(variant_type)) => {
+                            let variant_type = variant_type.to_type();
+                            let handler_type = handler.to_type();
+                            let (x, tx, tb) = match &*handler_type.as_whnf() {
+                                ValueF::Pi(x, tx, tb) => {
+                                    (x.clone(), tx.to_type(), tb.to_type())
+                                }
+                                _ => {
+                                    return Err(mkerr(NotAFunction(
+                                        handler_type.clone(),
+                                    )))
+                                }
+                            };
+
+                            if &variant_type != &tx {
+                                return Err(mkerr(TypeMismatch(
+                                    handler_type,
+                                    tx,
+                                    variant_type,
+                                )));
                             }
-                            _ => return Err(mkerr(NotAFunction(handler_type))),
-                        };
-
-                        if &variant_type != &tx {
-                            return Err(mkerr(TypeMismatch(
-                                handler_type,
-                                tx.to_normalized(),
-                                variant_type,
-                            )));
-                        }
 
-                        // Extract `tb` from under the `x` binder. Fails is `x` was free in `tb`.
-                        match tb.over_binder(x) {
-                            Some(x) => x,
-                            None => {
-                                return Err(mkerr(
+                            // Extract `tb` from under the `x` binder. Fails is `x` was free in `tb`.
+                            match tb.over_binder(x) {
+                                Some(x) => x,
+                                None => return Err(mkerr(
                                     MergeHandlerReturnTypeMustNotBeDependent,
-                                ))
+                                )),
                             }
                         }
-                    }
-                    // Union alternative without type
-                    Some(None) => handler.to_type(),
-                    None => {
-                        return Err(mkerr(MergeHandlerMissingVariant(
-                            x.clone(),
-                        )))
-                    }
-                };
+                        // Union alternative without type
+                        Some(None) => handler.to_type(),
+                        None => {
+                            return Err(mkerr(MergeHandlerMissingVariant(
+                                x.clone(),
+                            )))
+                        }
+                    };
                 match &inferred_type {
                     None => inferred_type = Some(handler_return_type),
                     Some(t) => {
@@ -974,8 +963,9 @@ fn type_last_layer(
             }
         }
         Projection(record, labels) => {
-            let trecord = record.get_type()?;
-            let kts = match trecord.to_valuef() {
+            let record_type = record.get_type()?;
+            let record_borrow = record_type.as_whnf();
+            let kts = match &*record_borrow {
                 ValueF::RecordType(kts) => kts,
                 _ => return Err(mkerr(ProjectionMustBeRecord)),
             };
@@ -991,7 +981,7 @@ fn type_last_layer(
             Ok(RetTypeOnly(
                 Typed::from_value_and_type(
                     ValueF::RecordType(new_kts).into_value(),
-                    trecord.get_type()?.into_owned(),
+                    record_type.get_type()?.into_owned(),
                 )
                 .to_type(),
             ))
diff --git a/dhall/src/tests.rs b/dhall/src/tests.rs
index 70cff46..44e22e4 100644
--- a/dhall/src/tests.rs
+++ b/dhall/src/tests.rs
@@ -185,7 +185,7 @@ pub fn run_test(
                 }
                 TypeInference => {
                     let expr = expr.typecheck()?;
-                    let ty = expr.get_type()?.to_normalized();
+                    let ty = expr.get_type()?.into_owned().normalize();
                     assert_eq_display!(ty, expected);
                 }
                 Normalization => {
-- 
cgit v1.3.1


From 26a1fd0f0861038a76a0f9b09eaef16d808d4139 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 19 Aug 2019 21:52:26 +0200
Subject: Use TypedValue instead of Typed in normalize and typecheck

Now Typed is only used in dhall::phase, similarly to
Parsed/Resolved/Normalized
---
 dhall/src/core/context.rs    |  29 ++--
 dhall/src/core/value.rs      |  48 +++---
 dhall/src/core/valuef.rs     |   6 +-
 dhall/src/error/mod.rs       |  55 +++---
 dhall/src/phase/mod.rs       |  51 ++----
 dhall/src/phase/normalize.rs |   6 +-
 dhall/src/phase/typecheck.rs | 392 +++++++++++++++++++------------------------
 dhall/src/tests.rs           |   2 +-
 serde_dhall/src/lib.rs       |  10 +-
 9 files changed, 260 insertions(+), 339 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index e1a23a9..851e4c4 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -3,16 +3,15 @@ use std::rc::Rc;
 
 use dhall_syntax::{Label, V};
 
-use crate::core::value::Value;
+use crate::core::value::{TypedValue, Value};
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::TypeError;
-use crate::phase::{Type, Typed};
 
 #[derive(Debug, Clone)]
 enum CtxItem {
-    Kept(AlphaVar, Type),
-    Replaced(Value, Type),
+    Kept(AlphaVar, TypedValue),
+    Replaced(Value, TypedValue),
 }
 
 #[derive(Debug, Clone)]
@@ -22,12 +21,16 @@ impl TypecheckContext {
     pub fn new() -> Self {
         TypecheckContext(Rc::new(Vec::new()))
     }
-    pub fn insert_type(&self, x: &Label, t: Type) -> Self {
+    pub fn insert_type(&self, x: &Label, t: TypedValue) -> Self {
         let mut vec = self.0.as_ref().clone();
         vec.push((x.clone(), CtxItem::Kept(x.into(), t.under_binder(x))));
         TypecheckContext(Rc::new(vec))
     }
-    pub fn insert_value(&self, x: &Label, e: Typed) -> Result<Self, TypeError> {
+    pub fn insert_value(
+        &self,
+        x: &Label,
+        e: TypedValue,
+    ) -> Result<Self, TypeError> {
         let mut vec = self.0.as_ref().clone();
         vec.push((
             x.clone(),
@@ -35,7 +38,7 @@ impl TypecheckContext {
         ));
         Ok(TypecheckContext(Rc::new(vec)))
     }
-    pub fn lookup(&self, var: &V<Label>) -> Option<Typed> {
+    pub fn lookup(&self, var: &V<Label>) -> Option<TypedValue> {
         let mut var = var.clone();
         let mut shift_map: HashMap<Label, _> = HashMap::new();
         for (l, i) in self.0.iter().rev() {
@@ -48,7 +51,7 @@ impl TypecheckContext {
                         }
                         CtxItem::Replaced(th, t) => (th, t),
                     };
-                    return Some(Typed::from_value_and_type(th, t));
+                    return Some(TypedValue::from_value_and_type(th, t));
                 }
                 Some(newvar) => var = newvar,
             };
@@ -99,7 +102,7 @@ impl TypecheckContext {
             )))
         }
     }
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         self.do_with_var(var, |var, i| Ok::<_, !>(i.subst_shift(&var, val)))
             .unwrap()
     }
@@ -124,8 +127,8 @@ impl Shift for TypecheckContext {
     }
 }
 
-impl Subst<Typed> for CtxItem {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+impl Subst<TypedValue> for CtxItem {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         match self {
             CtxItem::Replaced(e, t) => CtxItem::Replaced(
                 e.subst_shift(var, val),
@@ -141,8 +144,8 @@ impl Subst<Typed> for CtxItem {
     }
 }
 
-impl Subst<Typed> for TypecheckContext {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+impl Subst<TypedValue> for TypecheckContext {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         self.subst_shift(var, val)
     }
 }
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 213a2bd..f4cb6b6 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -10,7 +10,7 @@ use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::normalize::{apply_any, normalize_whnf, OutputSubExpr};
 use crate::phase::typecheck::type_of_const;
-use crate::phase::{Normalized, NormalizedSubExpr, Type, Typed};
+use crate::phase::{Normalized, NormalizedSubExpr, Typed};
 
 #[derive(Debug, Clone, Copy)]
 enum Form {
@@ -35,12 +35,12 @@ use Form::{Unevaled, NF, WHNF};
 struct ValueInternal {
     form: Form,
     value: ValueF,
-    ty: Option<Type>,
+    ty: Option<TypedValue>,
 }
 
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
 /// sharing computation automatically. Uses a RefCell to share computation.
-/// Can optionally store a Type from typechecking to preserve type information through
+/// Can optionally store a type from typechecking to preserve type information through
 /// normalization.
 #[derive(Clone)]
 pub struct Value(Rc<RefCell<ValueInternal>>);
@@ -96,7 +96,7 @@ impl ValueInternal {
         }
     }
 
-    fn get_type(&self) -> Result<&Type, TypeError> {
+    fn get_type(&self) -> Result<&TypedValue, TypeError> {
         match &self.ty {
             Some(t) => Ok(t),
             None => Err(TypeError::new(
@@ -116,7 +116,7 @@ impl Value {
         }
         .into_value()
     }
-    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Value {
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: TypedValue) -> Value {
         ValueInternal {
             form: Unevaled,
             value: v,
@@ -128,7 +128,7 @@ impl Value {
         Value::from_valuef(ValueF::PartialExpr(e))
     }
     // TODO: avoid using this function
-    pub(crate) fn with_type(self, t: Type) -> Value {
+    pub(crate) fn with_type(self, t: TypedValue) -> Value {
         let vint = self.as_internal();
         ValueInternal {
             form: vint.form,
@@ -221,7 +221,7 @@ impl Value {
         apply_any(self.clone(), th)
     }
 
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, TypedValue>, TypeError> {
         Ok(Cow::Owned(self.as_internal().get_type()?.clone()))
     }
 }
@@ -231,18 +231,10 @@ impl TypedValue {
         TypedValue::from_value_untyped(Value::from_valuef(v))
     }
 
-    pub(crate) fn from_type(t: Type) -> TypedValue {
-        t.into_typedvalue()
-    }
-
     pub(crate) fn normalize_nf(&self) -> ValueF {
         self.0.normalize_nf().clone()
     }
 
-    pub(crate) fn to_typed(&self) -> Typed {
-        self.clone().into_typed()
-    }
-
     pub(crate) fn normalize_to_expr_maybe_alpha(
         &self,
         alpha: bool,
@@ -250,11 +242,11 @@ impl TypedValue {
         self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub(crate) fn from_value_and_type(th: Value, t: Type) -> Self {
+    pub(crate) fn from_value_and_type(th: Value, t: TypedValue) -> Self {
         TypedValue(th.with_type(t))
     }
     pub fn from_value_simple_type(th: Value) -> Self {
-        TypedValue::from_value_and_type(th, Type::const_type())
+        TypedValue::from_value_and_type(th, TypedValue::const_type())
     }
     pub(crate) fn from_value_untyped(th: Value) -> Self {
         TypedValue(th)
@@ -265,7 +257,10 @@ impl TypedValue {
             Err(_) => TypedValue::from_valuef(ValueF::Const(c)),
         }
     }
-    pub(crate) fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
+    pub fn const_type() -> Self {
+        TypedValue::from_const(Const::Type)
+    }
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: TypedValue) -> Self {
         TypedValue(Value::from_valuef_and_type(v, t))
     }
 
@@ -286,9 +281,6 @@ impl TypedValue {
     pub(crate) fn to_value(&self) -> Value {
         self.0.clone()
     }
-    pub(crate) fn to_type(&self) -> Type {
-        self.clone().into_typed().into_type()
-    }
     pub(crate) fn into_typed(self) -> Typed {
         Typed::from_typedvalue(self)
     }
@@ -303,7 +295,7 @@ impl TypedValue {
         self.0.normalize_mut()
     }
 
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, TypedValue>, TypeError> {
         self.0.get_type()
     }
 }
@@ -330,14 +322,14 @@ impl Shift for TypedValue {
     }
 }
 
-impl Subst<Typed> for Value {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+impl Subst<TypedValue> for Value {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         Value(self.0.subst_shift(var, val))
     }
 }
 
-impl Subst<Typed> for ValueInternal {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+impl Subst<TypedValue> for ValueInternal {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         ValueInternal {
             // The resulting value may not stay in wnhf after substitution
             form: Unevaled,
@@ -347,8 +339,8 @@ impl Subst<Typed> for ValueInternal {
     }
 }
 
-impl Subst<Typed> for TypedValue {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+impl Subst<TypedValue> for TypedValue {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         TypedValue(self.0.subst_shift(var, val))
     }
 }
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 0ba1d59..b948eb1 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -8,7 +8,7 @@ use dhall_syntax::{
 use crate::core::value::{TypedValue, Value};
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::normalize::OutputSubExpr;
-use crate::phase::{Normalized, Typed};
+use crate::phase::Normalized;
 
 /// A semantic value. Subexpressions are Values, which are partially evaluated expressions that are
 /// normalized on-demand.
@@ -327,8 +327,8 @@ impl Shift for ValueF {
     }
 }
 
-impl Subst<Typed> for ValueF {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+impl Subst<TypedValue> for ValueF {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         match self {
             ValueF::AppliedBuiltin(b, args) => {
                 ValueF::AppliedBuiltin(*b, args.subst_shift(var, val))
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 34a89c0..0f2f5fc 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -3,8 +3,9 @@ use std::io::Error as IOError;
 use dhall_syntax::{BinOp, Import, Label, ParseError, V};
 
 use crate::core::context::TypecheckContext;
+use crate::core::value::TypedValue;
 use crate::phase::resolve::ImportStack;
-use crate::phase::{NormalizedSubExpr, Type, Typed};
+use crate::phase::NormalizedSubExpr;
 
 pub type Result<T> = std::result::Result<T, Error>;
 
@@ -48,28 +49,28 @@ pub struct TypeError {
 #[derive(Debug)]
 pub(crate) enum TypeMessage {
     UnboundVariable(V<Label>),
-    InvalidInputType(Typed),
-    InvalidOutputType(Typed),
-    NotAFunction(Typed),
-    TypeMismatch(Typed, Typed, Typed),
-    AnnotMismatch(Typed, Typed),
+    InvalidInputType(TypedValue),
+    InvalidOutputType(TypedValue),
+    NotAFunction(TypedValue),
+    TypeMismatch(TypedValue, TypedValue, TypedValue),
+    AnnotMismatch(TypedValue, TypedValue),
     Untyped,
     FieldCollision(Label),
-    InvalidListElement(usize, Typed, Typed),
-    InvalidListType(Typed),
-    InvalidOptionalType(Typed),
-    InvalidPredicate(Typed),
-    IfBranchMismatch(Typed, Typed),
-    IfBranchMustBeTerm(bool, Typed),
-    InvalidFieldType(Label, Type),
-    NotARecord(Label, Typed),
-    MustCombineRecord(Typed),
-    MissingRecordField(Label, Typed),
-    MissingUnionField(Label, Typed),
-    BinOpTypeMismatch(BinOp, Typed),
-    InvalidTextInterpolation(Typed),
-    Merge1ArgMustBeRecord(Typed),
-    Merge2ArgMustBeUnion(Typed),
+    InvalidListElement(usize, TypedValue, TypedValue),
+    InvalidListType(TypedValue),
+    InvalidOptionalType(TypedValue),
+    InvalidPredicate(TypedValue),
+    IfBranchMismatch(TypedValue, TypedValue),
+    IfBranchMustBeTerm(bool, TypedValue),
+    InvalidFieldType(Label, TypedValue),
+    NotARecord(Label, TypedValue),
+    MustCombineRecord(TypedValue),
+    MissingRecordField(Label, TypedValue),
+    MissingUnionField(Label, TypedValue),
+    BinOpTypeMismatch(BinOp, TypedValue),
+    InvalidTextInterpolation(TypedValue),
+    Merge1ArgMustBeRecord(TypedValue),
+    Merge2ArgMustBeUnion(TypedValue),
     MergeEmptyNeedsAnnotation,
     MergeHandlerMissingVariant(Label),
     MergeVariantMissingHandler(Label),
@@ -79,14 +80,14 @@ pub(crate) enum TypeMessage {
     ProjectionMustBeRecord,
     ProjectionMissingEntry,
     Sort,
-    RecordMismatch(Typed, Typed),
+    RecordMismatch(TypedValue, TypedValue),
     RecordTypeDuplicateField,
-    RecordTypeMergeRequiresRecordType(Type),
-    RecordTypeMismatch(Type, Type, Type, Type),
+    RecordTypeMergeRequiresRecordType(TypedValue),
+    RecordTypeMismatch(TypedValue, TypedValue, TypedValue, TypedValue),
     UnionTypeDuplicateField,
-    EquivalenceArgumentMustBeTerm(bool, Typed),
-    EquivalenceTypeMismatch(Typed, Typed),
-    AssertMismatch(Typed, Typed),
+    EquivalenceArgumentMustBeTerm(bool, TypedValue),
+    EquivalenceTypeMismatch(TypedValue, TypedValue),
+    AssertMismatch(TypedValue, TypedValue),
     AssertMustTakeEquivalence,
 }
 
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index a38e9d3..e58e689 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -1,5 +1,4 @@
 use std::borrow::Cow;
-use std::cell::Ref;
 use std::fmt::Display;
 use std::path::Path;
 
@@ -42,8 +41,6 @@ pub struct Typed(TypedValue);
 #[derive(Debug, Clone)]
 pub struct Normalized(Typed);
 
-pub type Type = Typed;
-
 impl Parsed {
     pub fn parse_file(f: &Path) -> Result<Parsed, Error> {
         parse::parse_file(f)
@@ -72,10 +69,10 @@ impl Parsed {
 
 impl Resolved {
     pub fn typecheck(self) -> Result<Typed, TypeError> {
-        typecheck::typecheck(self)
+        Ok(typecheck::typecheck(self.0)?.into_typed())
     }
-    pub fn typecheck_with(self, ty: &Type) -> Result<Typed, TypeError> {
-        typecheck::typecheck_with(self, ty)
+    pub fn typecheck_with(self, ty: &Typed) -> Result<Typed, TypeError> {
+        Ok(typecheck::typecheck_with(self.0, ty.to_expr())?.into_typed())
     }
 }
 
@@ -93,17 +90,11 @@ impl Typed {
         Normalized(self)
     }
 
-    pub(crate) fn from_value_and_type(th: Value, t: Type) -> Self {
-        Typed(TypedValue::from_value_and_type(th, t))
-    }
-    pub(crate) fn from_value_untyped(th: Value) -> Self {
-        Typed(TypedValue::from_value_untyped(th))
-    }
     pub(crate) fn from_const(c: Const) -> Self {
         Typed(TypedValue::from_const(c))
     }
-    pub fn from_valuef_and_type(v: ValueF, t: Type) -> Self {
-        Typed(TypedValue::from_valuef_and_type(v, t))
+    pub fn from_valuef_and_type(v: ValueF, t: Typed) -> Self {
+        Typed(TypedValue::from_valuef_and_type(v, t.into_typedvalue()))
     }
     pub(crate) fn from_typedvalue(th: TypedValue) -> Self {
         Typed(th)
@@ -112,14 +103,6 @@ impl Typed {
         Typed::from_const(Const::Type)
     }
 
-    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
-    /// panics.
-    pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
-        self.0.as_whnf()
-    }
-    pub(crate) fn to_whnf(&self) -> ValueF {
-        self.0.to_whnf()
-    }
     pub fn to_expr(&self) -> NormalizedSubExpr {
         self.0.to_expr()
     }
@@ -129,27 +112,17 @@ impl Typed {
     pub fn to_value(&self) -> Value {
         self.0.to_value()
     }
-    // Deprecated
-    pub fn to_type(&self) -> Type {
-        self.clone()
-    }
-    // Deprecated
-    pub(crate) fn into_type(self) -> Type {
-        self
-    }
     pub(crate) fn into_typedvalue(self) -> TypedValue {
         self.0
     }
-    pub(crate) fn as_const(&self) -> Option<Const> {
-        self.0.as_const()
-    }
 
     pub(crate) fn normalize_mut(&mut self) {
         self.0.normalize_mut()
     }
 
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
-        self.0.get_type()
+    #[allow(dead_code)]
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, Typed>, TypeError> {
+        Ok(Cow::Owned(self.0.get_type()?.into_owned().into_typed()))
     }
 }
 
@@ -165,10 +138,6 @@ impl Normalized {
     pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.0.to_expr_alpha()
     }
-    #[allow(dead_code)]
-    pub(crate) fn to_type(&self) -> Type {
-        self.0.to_type()
-    }
     pub(crate) fn into_typed(self) -> Typed {
         self.0
     }
@@ -186,8 +155,8 @@ impl Shift for Normalized {
     }
 }
 
-impl Subst<Typed> for Typed {
-    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+impl Subst<TypedValue> for Typed {
+    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         Typed(self.0.subst_shift(var, val))
     }
 }
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 785a75f..dabfe87 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -8,7 +8,7 @@ use dhall_syntax::{
 use crate::core::value::{TypedValue, Value};
 use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
-use crate::phase::{Normalized, NormalizedSubExpr, Typed};
+use crate::phase::{Normalized, NormalizedSubExpr};
 
 pub(crate) type OutputSubExpr = NormalizedSubExpr;
 
@@ -327,7 +327,7 @@ pub(crate) fn apply_any(f: Value, a: Value) -> ValueF {
     let f_borrow = f.as_whnf();
     match &*f_borrow {
         ValueF::Lam(x, _, e) => {
-            let val = Typed::from_value_untyped(a);
+            let val = TypedValue::from_value_untyped(a);
             e.subst_shift(&x.into(), &val).to_whnf()
         }
         ValueF::AppliedBuiltin(b, args) => {
@@ -663,7 +663,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
             TypedValue::from_value_untyped(e),
         )),
         ExprF::Let(x, _, v, b) => {
-            let v = Typed::from_value_untyped(v);
+            let v = TypedValue::from_value_untyped(v);
             Ret::Value(b.subst_shift(&x.into(), &v))
         }
         ExprF::App(v, a) => Ret::ValueF(v.app_value(a)),
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index c303ada..07c4ad8 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -9,14 +9,14 @@ use crate::core::value::{TypedValue, Value};
 use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
-use crate::phase::{Normalized, Resolved, Type, Typed};
+use crate::phase::Normalized;
 
 fn tck_pi_type(
     ctx: &TypecheckContext,
     x: Label,
-    tx: Type,
-    te: Type,
-) -> Result<Typed, TypeError> {
+    tx: TypedValue,
+    te: TypedValue,
+) -> Result<TypedValue, TypeError> {
     use crate::error::TypeMessage::*;
     let ctx2 = ctx.insert_type(&x, tx.clone());
 
@@ -37,21 +37,16 @@ fn tck_pi_type(
 
     let k = function_check(ka, kb);
 
-    Ok(Typed::from_value_and_type(
-        ValueF::Pi(
-            x.into(),
-            TypedValue::from_type(tx),
-            TypedValue::from_type(te),
-        )
-        .into_value(),
-        Type::from_const(k),
+    Ok(TypedValue::from_value_and_type(
+        ValueF::Pi(x.into(), tx, te).into_value(),
+        TypedValue::from_const(k),
     ))
 }
 
 fn tck_record_type(
     ctx: &TypecheckContext,
-    kts: impl IntoIterator<Item = Result<(Label, Type), TypeError>>,
-) -> Result<Typed, TypeError> {
+    kts: impl IntoIterator<Item = Result<(Label, TypedValue), TypeError>>,
+) -> Result<TypedValue, TypeError> {
     use crate::error::TypeMessage::*;
     use std::collections::hash_map::Entry;
     let mut new_kts = HashMap::new();
@@ -62,36 +57,32 @@ fn tck_record_type(
         match (k, t.get_type()?.as_const()) {
             (None, Some(k2)) => k = Some(k2),
             (Some(k1), Some(k2)) if k1 == k2 => {}
-            _ => {
-                return Err(TypeError::new(
-                    ctx,
-                    InvalidFieldType(x.clone(), t.clone()),
-                ))
-            }
+            _ => return Err(TypeError::new(ctx, InvalidFieldType(x, t))),
         }
-        let entry = new_kts.entry(x.clone());
+        let entry = new_kts.entry(x);
         match &entry {
             Entry::Occupied(_) => {
                 return Err(TypeError::new(ctx, RecordTypeDuplicateField))
             }
-            Entry::Vacant(_) => {
-                entry.or_insert_with(|| TypedValue::from_type(t.clone()))
-            }
+            Entry::Vacant(_) => entry.or_insert_with(|| t),
         };
     }
     // An empty record type has type Type
-    let k = k.unwrap_or(dhall_syntax::Const::Type);
+    let k = k.unwrap_or(Const::Type);
 
-    Ok(Typed::from_value_and_type(
+    Ok(TypedValue::from_value_and_type(
         ValueF::RecordType(new_kts).into_value(),
-        Type::from_const(k),
+        TypedValue::from_const(k),
     ))
 }
 
-fn tck_union_type(
+fn tck_union_type<Iter>(
     ctx: &TypecheckContext,
-    kts: impl IntoIterator<Item = Result<(Label, Option<Type>), TypeError>>,
-) -> Result<Typed, TypeError> {
+    kts: Iter,
+) -> Result<TypedValue, TypeError>
+where
+    Iter: IntoIterator<Item = Result<(Label, Option<TypedValue>), TypeError>>,
+{
     use crate::error::TypeMessage::*;
     use std::collections::hash_map::Entry;
     let mut new_kts = HashMap::new();
@@ -106,46 +97,43 @@ fn tck_union_type(
                 _ => {
                     return Err(TypeError::new(
                         ctx,
-                        InvalidFieldType(x.clone(), t.clone()),
+                        InvalidFieldType(x, t.clone()),
                     ))
                 }
             }
         }
-        let entry = new_kts.entry(x.clone());
+        let entry = new_kts.entry(x);
         match &entry {
             Entry::Occupied(_) => {
                 return Err(TypeError::new(ctx, UnionTypeDuplicateField))
             }
-            Entry::Vacant(_) => entry.or_insert_with(|| {
-                t.as_ref().map(|t| TypedValue::from_type(t.clone()))
-            }),
+            Entry::Vacant(_) => entry.or_insert_with(|| t),
         };
     }
 
     // An empty union type has type Type;
     // an union type with only unary variants also has type Type
-    let k = k.unwrap_or(dhall_syntax::Const::Type);
+    let k = k.unwrap_or(Const::Type);
 
-    Ok(Typed::from_value_and_type(
+    Ok(TypedValue::from_value_and_type(
         ValueF::UnionType(new_kts).into_value(),
-        Type::from_const(k),
+        TypedValue::from_const(k),
     ))
 }
 
 fn function_check(a: Const, b: Const) -> Const {
-    use dhall_syntax::Const::Type;
     use std::cmp::max;
-    if b == Type {
-        Type
+    if b == Const::Type {
+        Const::Type
     } else {
         max(a, b)
     }
 }
 
-pub(crate) fn type_of_const(c: Const) -> Result<Type, TypeError> {
+pub(crate) fn type_of_const(c: Const) -> Result<TypedValue, TypeError> {
     match c {
-        Const::Type => Ok(Type::from_const(Const::Kind)),
-        Const::Kind => Ok(Type::from_const(Const::Sort)),
+        Const::Type => Ok(TypedValue::from_const(Const::Kind)),
+        Const::Kind => Ok(TypedValue::from_const(Const::Sort)),
         Const::Sort => {
             Err(TypeError::new(&TypecheckContext::new(), TypeMessage::Sort))
         }
@@ -293,25 +281,16 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
     }
 }
 
-/// Takes an expression that is meant to contain a Type
-/// and turn it into a type, typechecking it along the way.
-pub(crate) fn mktype(
-    ctx: &TypecheckContext,
-    e: SubExpr<Normalized>,
-) -> Result<Type, TypeError> {
-    Ok(type_with(ctx, e)?.to_type())
-}
-
-pub(crate) fn builtin_to_type(b: Builtin) -> Result<Type, TypeError> {
-    mktype(&TypecheckContext::new(), SubExpr::from_builtin(b))
+pub(crate) fn builtin_to_type(b: Builtin) -> Result<TypedValue, TypeError> {
+    type_with(&TypecheckContext::new(), SubExpr::from_builtin(b))
 }
 
 /// Intermediary return type
 enum Ret {
     /// Returns the contained value as is
-    RetWhole(Typed),
-    /// Use the contained Type as the type of the input expression
-    RetTypeOnly(Type),
+    RetWhole(TypedValue),
+    /// Use the contained TypedValue as the type of the input expression
+    RetTypeOnly(TypedValue),
 }
 
 /// Type-check an expression and return the expression alongside its type if type-checking
@@ -321,28 +300,24 @@ enum Ret {
 fn type_with(
     ctx: &TypecheckContext,
     e: SubExpr<Normalized>,
-) -> Result<Typed, TypeError> {
+) -> Result<TypedValue, TypeError> {
     use dhall_syntax::ExprF::{Annot, Embed, Lam, Let, Pi, Var};
 
     use Ret::*;
     Ok(match e.as_ref() {
         Lam(x, t, b) => {
-            let tx = mktype(ctx, t.clone())?;
+            let tx = type_with(ctx, t.clone())?;
             let ctx2 = ctx.insert_type(x, tx.clone());
             let b = type_with(&ctx2, b.clone())?;
-            let v = ValueF::Lam(
-                x.clone().into(),
-                TypedValue::from_type(tx.clone()),
-                b.to_value(),
-            );
+            let v = ValueF::Lam(x.clone().into(), tx.clone(), b.to_value());
             let tb = b.get_type()?.into_owned();
-            let t = tck_pi_type(ctx, x.clone(), tx, tb)?.to_type();
-            Typed::from_value_and_type(Value::from_valuef(v), t)
+            let t = tck_pi_type(ctx, x.clone(), tx, tb)?;
+            TypedValue::from_valuef_and_type(v, t)
         }
         Pi(x, ta, tb) => {
-            let ta = mktype(ctx, ta.clone())?;
+            let ta = type_with(ctx, ta.clone())?;
             let ctx2 = ctx.insert_type(x, ta.clone());
-            let tb = mktype(&ctx2, tb.clone())?;
+            let tb = type_with(&ctx2, tb.clone())?;
             return tck_pi_type(ctx, x.clone(), ta, tb);
         }
         Let(x, t, v, e) => {
@@ -355,9 +330,9 @@ fn type_with(
             let v = type_with(ctx, v)?;
             return type_with(&ctx.insert_value(x, v.clone())?, e.clone());
         }
-        Embed(p) => p.clone().into_typed(),
+        Embed(p) => p.clone().into_typed().into_typedvalue(),
         Var(var) => match ctx.lookup(&var) {
-            Some(typed) => typed,
+            Some(typed) => typed.clone(),
             None => {
                 return Err(TypeError::new(
                     ctx,
@@ -376,7 +351,7 @@ fn type_with(
             match ret {
                 RetTypeOnly(typ) => {
                     let expr = expr.map_ref(|typed| typed.to_value());
-                    Typed::from_value_and_type(
+                    TypedValue::from_value_and_type(
                         Value::from_partial_expr(expr),
                         typ,
                     )
@@ -391,7 +366,7 @@ fn type_with(
 /// layer.
 fn type_last_layer(
     ctx: &TypecheckContext,
-    e: &ExprF<Typed, Normalized>,
+    e: &ExprF<TypedValue, Normalized>,
 ) -> Result<Ret, TypeError> {
     use crate::error::TypeMessage::*;
     use dhall_syntax::BinOp::*;
@@ -410,22 +385,24 @@ fn type_last_layer(
         }
         App(f, a) => {
             let tf = f.get_type()?;
-            let (x, tx, tb) = match &*tf.as_whnf() {
-                ValueF::Pi(x, tx, tb) => {
-                    (x.clone(), tx.to_type(), tb.to_type())
-                }
+            let tf_borrow = tf.as_whnf();
+            let (x, tx, tb) = match &*tf_borrow {
+                ValueF::Pi(x, tx, tb) => (x, tx, tb),
                 _ => return Err(mkerr(NotAFunction(f.clone()))),
             };
-            if a.get_type()?.as_ref() != &tx {
-                return Err(mkerr(TypeMismatch(f.clone(), tx, a.clone())));
+            if a.get_type()?.as_ref() != tx {
+                return Err(mkerr(TypeMismatch(
+                    f.clone(),
+                    tx.clone(),
+                    a.clone(),
+                )));
             }
 
-            Ok(RetTypeOnly(tb.subst_shift(&x.into(), &a)))
+            Ok(RetTypeOnly(tb.subst_shift(&x.into(), a)))
         }
         Annot(x, t) => {
-            let t = t.to_type();
-            if &t != x.get_type()?.as_ref() {
-                return Err(mkerr(AnnotMismatch(x.clone(), t)));
+            if t != x.get_type()?.as_ref() {
+                return Err(mkerr(AnnotMismatch(x.clone(), t.clone())));
             }
             Ok(RetTypeOnly(x.get_type()?.into_owned()))
         }
@@ -433,14 +410,11 @@ fn type_last_layer(
             match &*t.as_whnf() {
                 ValueF::Equivalence(x, y) if x == y => {}
                 ValueF::Equivalence(x, y) => {
-                    return Err(mkerr(AssertMismatch(
-                        x.to_typed(),
-                        y.to_typed(),
-                    )))
+                    return Err(mkerr(AssertMismatch(x.clone(), y.clone())))
                 }
                 _ => return Err(mkerr(AssertMustTakeEquivalence)),
             }
-            Ok(RetTypeOnly(t.to_type()))
+            Ok(RetTypeOnly(t.clone()))
         }
         BoolIf(x, y, z) => {
             if x.get_type()?.as_ref() != &builtin_to_type(Bool)? {
@@ -462,7 +436,6 @@ fn type_last_layer(
             Ok(RetTypeOnly(y.get_type()?.into_owned()))
         }
         EmptyListLit(t) => {
-            let t = t.to_type();
             match &*t.as_whnf() {
                 ValueF::AppliedBuiltin(dhall_syntax::Builtin::List, args)
                     if args.len() == 1 => {}
@@ -470,7 +443,7 @@ fn type_last_layer(
                     return Err(TypeError::new(ctx, InvalidListType(t.clone())))
                 }
             }
-            Ok(RetTypeOnly(t))
+            Ok(RetTypeOnly(t.clone()))
         }
         NEListLit(xs) => {
             let mut iter = xs.iter().enumerate();
@@ -492,15 +465,12 @@ fn type_last_layer(
                 ));
             }
 
-            Ok(RetTypeOnly(
-                Typed::from_value_and_type(
-                    ValueF::from_builtin(dhall_syntax::Builtin::List)
-                        .app_value(t.to_value())
-                        .into_value(),
-                    Typed::from_const(Type),
-                )
-                .to_type(),
-            ))
+            Ok(RetTypeOnly(TypedValue::from_value_and_type(
+                ValueF::from_builtin(dhall_syntax::Builtin::List)
+                    .app_value(t.to_value())
+                    .into_value(),
+                TypedValue::from_const(Type),
+            )))
         }
         SomeLit(x) => {
             let t = x.get_type()?.into_owned();
@@ -508,38 +478,31 @@ fn type_last_layer(
                 return Err(TypeError::new(ctx, InvalidOptionalType(t)));
             }
 
-            Ok(RetTypeOnly(
-                Typed::from_value_and_type(
-                    ValueF::from_builtin(dhall_syntax::Builtin::Optional)
-                        .app_value(t.to_value())
-                        .into_value(),
-                    Typed::from_const(Type).into_type(),
-                )
-                .to_type(),
-            ))
+            Ok(RetTypeOnly(TypedValue::from_value_and_type(
+                ValueF::from_builtin(dhall_syntax::Builtin::Optional)
+                    .app_value(t.to_value())
+                    .into_value(),
+                TypedValue::from_const(Type),
+            )))
         }
         RecordType(kts) => Ok(RetWhole(tck_record_type(
             ctx,
-            kts.iter().map(|(x, t)| Ok((x.clone(), t.to_type()))),
+            kts.iter().map(|(x, t)| Ok((x.clone(), t.clone()))),
         )?)),
         UnionType(kts) => Ok(RetWhole(tck_union_type(
             ctx,
-            kts.iter()
-                .map(|(x, t)| Ok((x.clone(), t.as_ref().map(|t| t.to_type())))),
+            kts.iter().map(|(x, t)| Ok((x.clone(), t.clone()))),
+        )?)),
+        RecordLit(kvs) => Ok(RetTypeOnly(tck_record_type(
+            ctx,
+            kvs.iter()
+                .map(|(x, v)| Ok((x.clone(), v.get_type()?.into_owned()))),
         )?)),
-        RecordLit(kvs) => Ok(RetTypeOnly(
-            tck_record_type(
-                ctx,
-                kvs.iter()
-                    .map(|(x, v)| Ok((x.clone(), v.get_type()?.into_owned()))),
-            )?
-            .into_type(),
-        )),
         Field(r, x) => {
             match &*r.get_type()?.as_whnf() {
                 ValueF::RecordType(kts) => match kts.get(&x) {
                     Some(tth) => {
-                        Ok(RetTypeOnly(tth.to_type()))
+                        Ok(RetTypeOnly(tth.clone()))
                     },
                     None => Err(mkerr(MissingRecordField(x.clone(),
                                         r.clone()))),
@@ -554,9 +517,9 @@ fn type_last_layer(
                                     tck_pi_type(
                                         ctx,
                                         "_".into(),
-                                        t.to_type(),
+                                        t.clone(),
                                         r.under_binder(Label::from("_")),
-                                    )?.to_type()
+                                    )?
                                 ))
                             },
                             Some(None) => {
@@ -579,12 +542,12 @@ fn type_last_layer(
                 }
                 // _ => Err(mkerr(NotARecord(
                 //     x,
-                //     r.to_type()?,
+                //     r?,
                 // ))),
             }
         }
-        Const(c) => Ok(RetWhole(Typed::from_const(*c))),
-        Builtin(b) => Ok(RetTypeOnly(mktype(ctx, rc(type_of_builtin(*b)))?)),
+        Const(c) => Ok(RetWhole(TypedValue::from_const(*c))),
+        Builtin(b) => Ok(RetTypeOnly(type_with(ctx, rc(type_of_builtin(*b)))?)),
         BoolLit(_) => Ok(RetTypeOnly(builtin_to_type(Bool)?)),
         NaturalLit(_) => Ok(RetTypeOnly(builtin_to_type(Natural)?)),
         IntegerLit(_) => Ok(RetTypeOnly(builtin_to_type(Integer)?)),
@@ -635,13 +598,10 @@ fn type_last_layer(
             let kts = merge_maps(kts_x, kts_y, |_, r_t| r_t.clone());
 
             // Construct the final record type from the union
-            Ok(RetTypeOnly(
-                tck_record_type(
-                    ctx,
-                    kts.iter().map(|(x, v)| Ok((x.clone(), v.to_type()))),
-                )?
-                .into_type(),
-            ))
+            Ok(RetTypeOnly(tck_record_type(
+                ctx,
+                kts.into_iter().map(|(x, v)| Ok((x.clone(), v))),
+            )?))
         }
         BinOp(RecursiveRecordMerge, l, r) => {
             // A recursive function to dig down into
@@ -650,42 +610,46 @@ fn type_last_layer(
                 ctx: &TypecheckContext,
                 kts_l: &HashMap<Label, TypedValue>,
                 kts_r: &HashMap<Label, TypedValue>,
-            ) -> Result<Typed, TypeError> {
+            ) -> Result<TypedValue, TypeError> {
                 use crate::phase::normalize::outer_join;
 
-                // If the Label exists for both records and Type for the values
+                // If the Label exists for both records and the values
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
-                let combine = |k: &Label,
-                               inner_l: &TypedValue,
-                               inner_r: &TypedValue|
-                 -> Result<Typed, TypeError> {
-                    match (&*inner_l.as_whnf(), &*inner_r.as_whnf()) {
-                        (
-                            ValueF::RecordType(inner_l_kvs),
-                            ValueF::RecordType(inner_r_kvs),
-                        ) => {
-                            combine_record_types(ctx, inner_l_kvs, inner_r_kvs)
+                let combine =
+                    |k: &Label,
+                     inner_l: &TypedValue,
+                     inner_r: &TypedValue|
+                     -> Result<TypedValue, TypeError> {
+                        match (&*inner_l.as_whnf(), &*inner_r.as_whnf()) {
+                            (
+                                ValueF::RecordType(inner_l_kvs),
+                                ValueF::RecordType(inner_r_kvs),
+                            ) => combine_record_types(
+                                ctx,
+                                inner_l_kvs,
+                                inner_r_kvs,
+                            ),
+                            (_, _) => Err(TypeError::new(
+                                ctx,
+                                FieldCollision(k.clone()),
+                            )),
                         }
-                        (_, _) => {
-                            Err(TypeError::new(ctx, FieldCollision(k.clone())))
-                        }
-                    }
-                };
+                    };
 
-                let kts: HashMap<Label, Result<Typed, TypeError>> = outer_join(
-                    |l| Ok(l.to_type()),
-                    |r| Ok(r.to_type()),
-                    combine,
-                    kts_l,
-                    kts_r,
-                );
+                let kts: HashMap<Label, Result<TypedValue, TypeError>> =
+                    outer_join(
+                        |l| Ok(l.clone()),
+                        |r| Ok(r.clone()),
+                        combine,
+                        kts_l,
+                        kts_r,
+                    );
 
                 Ok(tck_record_type(
                     ctx,
                     kts.into_iter().map(|(x, v)| v.map(|r| (x.clone(), r))),
-                )?
-                .into_type())
+                )?)
             };
 
             let l_type = l.get_type()?;
@@ -723,36 +687,40 @@ fn type_last_layer(
                 ctx: &TypecheckContext,
                 kts_l: &HashMap<Label, TypedValue>,
                 kts_r: &HashMap<Label, TypedValue>,
-            ) -> Result<Typed, TypeError> {
+            ) -> Result<TypedValue, TypeError> {
                 use crate::phase::normalize::intersection_with_key;
 
-                // If the Label exists for both records and Type for the values
+                // If the Label exists for both records and the values
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
-                let combine = |k: &Label,
-                               kts_l_inner: &TypedValue,
-                               kts_r_inner: &TypedValue|
-                 -> Result<Typed, TypeError> {
-                    match (&*kts_l_inner.as_whnf(), &*kts_r_inner.as_whnf()) {
-                        (
-                            ValueF::RecordType(kvs_l_inner),
-                            ValueF::RecordType(kvs_r_inner),
-                        ) => {
-                            combine_record_types(ctx, kvs_l_inner, kvs_r_inner)
+                let combine =
+                    |k: &Label,
+                     kts_l_inner: &TypedValue,
+                     kts_r_inner: &TypedValue|
+                     -> Result<TypedValue, TypeError> {
+                        match (&*kts_l_inner.as_whnf(), &*kts_r_inner.as_whnf())
+                        {
+                            (
+                                ValueF::RecordType(kvs_l_inner),
+                                ValueF::RecordType(kvs_r_inner),
+                            ) => combine_record_types(
+                                ctx,
+                                kvs_l_inner,
+                                kvs_r_inner,
+                            ),
+                            (_, _) => Err(TypeError::new(
+                                ctx,
+                                FieldCollision(k.clone()),
+                            )),
                         }
-                        (_, _) => {
-                            Err(TypeError::new(ctx, FieldCollision(k.clone())))
-                        }
-                    }
-                };
+                    };
 
                 let kts = intersection_with_key(combine, kts_l, kts_r);
 
                 Ok(tck_record_type(
                     ctx,
                     kts.into_iter().map(|(x, v)| v.map(|r| (x.clone(), r))),
-                )?
-                .into_type())
+                )?)
             };
 
             // Extract the Const of the LHS
@@ -780,8 +748,8 @@ fn type_last_layer(
                 k_l
             } else {
                 return Err(mkerr(RecordTypeMismatch(
-                    Typed::from_const(k_l),
-                    Typed::from_const(k_r),
+                    TypedValue::from_const(k_l),
+                    TypedValue::from_const(k_r),
                     l.clone(),
                     r.clone(),
                 )));
@@ -812,7 +780,7 @@ fn type_last_layer(
             // Ensure that the records combine without a type error
             // and if not output the final Const value.
             combine_record_types(ctx, kts_x, kts_y)
-                .and(Ok(RetTypeOnly(Typed::from_const(k))))
+                .and(Ok(RetTypeOnly(TypedValue::from_const(k))))
         }
         BinOp(o @ ListAppend, l, r) => {
             match &*l.get_type()?.as_whnf() {
@@ -847,7 +815,7 @@ fn type_last_layer(
                 )));
             }
 
-            Ok(RetTypeOnly(Typed::from_const(Type).into_type()))
+            Ok(RetTypeOnly(TypedValue::from_const(Type)))
         }
         BinOp(o, l, r) => {
             let t = builtin_to_type(match o {
@@ -892,17 +860,14 @@ fn type_last_layer(
             };
 
             let mut inferred_type = None;
-            for (x, handler) in handlers {
+            for (x, handler_type) in handlers {
                 let handler_return_type =
                     match variants.get(x) {
                         // Union alternative with type
                         Some(Some(variant_type)) => {
-                            let variant_type = variant_type.to_type();
-                            let handler_type = handler.to_type();
-                            let (x, tx, tb) = match &*handler_type.as_whnf() {
-                                ValueF::Pi(x, tx, tb) => {
-                                    (x.clone(), tx.to_type(), tb.to_type())
-                                }
+                            let handler_type_borrow = handler_type.as_whnf();
+                            let (x, tx, tb) = match &*handler_type_borrow {
+                                ValueF::Pi(x, tx, tb) => (x, tx, tb),
                                 _ => {
                                     return Err(mkerr(NotAFunction(
                                         handler_type.clone(),
@@ -910,11 +875,11 @@ fn type_last_layer(
                                 }
                             };
 
-                            if &variant_type != &tx {
+                            if variant_type != tx {
                                 return Err(mkerr(TypeMismatch(
-                                    handler_type,
-                                    tx,
-                                    variant_type,
+                                    handler_type.clone(),
+                                    tx.clone(),
+                                    variant_type.clone(),
                                 )));
                             }
 
@@ -927,7 +892,7 @@ fn type_last_layer(
                             }
                         }
                         // Union alternative without type
-                        Some(None) => handler.to_type(),
+                        Some(None) => handler_type.clone(),
                         None => {
                             return Err(mkerr(MergeHandlerMissingVariant(
                                 x.clone(),
@@ -951,14 +916,13 @@ fn type_last_layer(
 
             match (inferred_type, type_annot) {
                 (Some(ref t1), Some(t2)) => {
-                    let t2 = t2.to_type();
-                    if t1 != &t2 {
+                    if t1 != t2 {
                         return Err(mkerr(MergeAnnotMismatch));
                     }
-                    Ok(RetTypeOnly(t2))
+                    Ok(RetTypeOnly(t2.clone()))
                 }
                 (Some(t), None) => Ok(RetTypeOnly(t)),
-                (None, Some(t)) => Ok(RetTypeOnly(t.to_type())),
+                (None, Some(t)) => Ok(RetTypeOnly(t.clone())),
                 (None, None) => Err(mkerr(MergeEmptyNeedsAnnotation)),
             }
         }
@@ -978,34 +942,26 @@ fn type_last_layer(
                 };
             }
 
-            Ok(RetTypeOnly(
-                Typed::from_value_and_type(
-                    ValueF::RecordType(new_kts).into_value(),
-                    record_type.get_type()?.into_owned(),
-                )
-                .to_type(),
-            ))
+            Ok(RetTypeOnly(TypedValue::from_value_and_type(
+                ValueF::RecordType(new_kts).into_value(),
+                record_type.get_type()?.into_owned(),
+            )))
         }
     }
 }
 
-/// `typeOf` is the same as `type_with` with an empty context, meaning that the
+/// `type_of` is the same as `type_with` with an empty context, meaning that the
 /// expression must be closed (i.e. no free variables), otherwise type-checking
 /// will fail.
-fn type_of(e: SubExpr<Normalized>) -> Result<Typed, TypeError> {
-    let ctx = TypecheckContext::new();
-    type_with(&ctx, e)
-}
-
-pub(crate) fn typecheck(e: Resolved) -> Result<Typed, TypeError> {
-    type_of(e.0)
+pub(crate) fn typecheck(
+    e: SubExpr<Normalized>,
+) -> Result<TypedValue, TypeError> {
+    type_with(&TypecheckContext::new(), e)
 }
 
 pub(crate) fn typecheck_with(
-    e: Resolved,
-    ty: &Type,
-) -> Result<Typed, TypeError> {
-    let expr: SubExpr<_> = e.0;
-    let ty: SubExpr<_> = ty.to_expr();
-    type_of(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
+    expr: SubExpr<Normalized>,
+    ty: SubExpr<Normalized>,
+) -> Result<TypedValue, TypeError> {
+    typecheck(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
 }
diff --git a/dhall/src/tests.rs b/dhall/src/tests.rs
index 44e22e4..be4805d 100644
--- a/dhall/src/tests.rs
+++ b/dhall/src/tests.rs
@@ -181,7 +181,7 @@ pub fn run_test(
                     assert_eq_display!(expr, expected);
                 }
                 Typecheck => {
-                    expr.typecheck_with(&expected.to_type())?.get_type()?;
+                    expr.typecheck_with(&expected.into_typed())?.get_type()?;
                 }
                 TypeInference => {
                     let expr = expr.typecheck()?;
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 48f311e..31643d0 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -127,7 +127,7 @@ pub mod value {
     use dhall::core::value::TypedValue as TypedThunk;
     use dhall::core::value::Value as Thunk;
     use dhall::core::valuef::ValueF as DhallValue;
-    use dhall::phase::{NormalizedSubExpr, Parsed, Type, Typed};
+    use dhall::phase::{NormalizedSubExpr, Parsed, Typed};
     use dhall_syntax::Builtin;
 
     use super::de::{Error, Result};
@@ -147,7 +147,7 @@ pub mod value {
             let resolved = Parsed::parse_str(s)?.resolve()?;
             let typed = match ty {
                 None => resolved.typecheck()?,
-                Some(t) => resolved.typecheck_with(&t.to_type())?,
+                Some(t) => resolved.typecheck_with(t.as_typed())?,
             };
             Ok(Value(typed))
         }
@@ -157,13 +157,13 @@ pub mod value {
         pub(crate) fn to_value(&self) -> Thunk {
             self.0.to_value()
         }
-        pub(crate) fn to_type(&self) -> Type {
-            self.0.to_type()
+        pub(crate) fn as_typed(&self) -> &Typed {
+            &self.0
         }
 
         /// Assumes that the given value has type `Type`.
         pub(crate) fn make_simple_type(v: DhallValue) -> Self {
-            Value(Typed::from_valuef_and_type(v, Type::const_type()))
+            Value(Typed::from_valuef_and_type(v, Typed::const_type()))
         }
         pub(crate) fn make_builtin_type(b: Builtin) -> Self {
             Self::make_simple_type(DhallValue::from_builtin(b))
-- 
cgit v1.3.1


From 07a276c1d6ee892b93abbd7a73c78c96d56f4fe7 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 19 Aug 2019 22:26:17 +0200
Subject: Reduce untyped construction of Values

---
 dhall/src/core/context.rs    | 34 ++++++++-------------
 dhall/src/core/value.rs      | 68 +++++++++++++++++------------------------
 dhall/src/core/valuef.rs     | 14 ++++++---
 dhall/src/phase/normalize.rs | 72 ++++++++++++++++++++++++++++----------------
 dhall/src/phase/typecheck.rs | 33 ++++++++++----------
 serde_dhall/src/lib.rs       |  9 ++----
 6 files changed, 115 insertions(+), 115 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index 851e4c4..deabe44 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -3,7 +3,7 @@ use std::rc::Rc;
 
 use dhall_syntax::{Label, V};
 
-use crate::core::value::{TypedValue, Value};
+use crate::core::value::TypedValue;
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::TypeError;
@@ -11,7 +11,7 @@ use crate::error::TypeError;
 #[derive(Debug, Clone)]
 enum CtxItem {
     Kept(AlphaVar, TypedValue),
-    Replaced(Value, TypedValue),
+    Replaced(TypedValue),
 }
 
 #[derive(Debug, Clone)]
@@ -32,10 +32,7 @@ impl TypecheckContext {
         e: TypedValue,
     ) -> Result<Self, TypeError> {
         let mut vec = self.0.as_ref().clone();
-        vec.push((
-            x.clone(),
-            CtxItem::Replaced(e.to_value(), e.get_type()?.into_owned()),
-        ));
+        vec.push((x.clone(), CtxItem::Replaced(e)));
         Ok(TypecheckContext(Rc::new(vec)))
     }
     pub fn lookup(&self, var: &V<Label>) -> Option<TypedValue> {
@@ -45,13 +42,15 @@ impl TypecheckContext {
             match var.over_binder(l) {
                 None => {
                     let i = i.under_multiple_binders(&shift_map);
-                    let (th, t) = match i {
+                    return Some(match i {
                         CtxItem::Kept(newvar, t) => {
-                            (ValueF::Var(newvar).into_value(), t)
+                            TypedValue::from_valuef_and_type(
+                                ValueF::Var(newvar),
+                                t,
+                            )
                         }
-                        CtxItem::Replaced(th, t) => (th, t),
-                    };
-                    return Some(TypedValue::from_value_and_type(th, t));
+                        CtxItem::Replaced(v) => v,
+                    });
                 }
                 Some(newvar) => var = newvar,
             };
@@ -114,9 +113,7 @@ impl Shift for CtxItem {
             CtxItem::Kept(v, t) => {
                 CtxItem::Kept(v.shift(delta, var)?, t.shift(delta, var)?)
             }
-            CtxItem::Replaced(e, t) => {
-                CtxItem::Replaced(e.shift(delta, var)?, t.shift(delta, var)?)
-            }
+            CtxItem::Replaced(e) => CtxItem::Replaced(e.shift(delta, var)?),
         })
     }
 }
@@ -130,14 +127,9 @@ impl Shift for TypecheckContext {
 impl Subst<TypedValue> for CtxItem {
     fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
         match self {
-            CtxItem::Replaced(e, t) => CtxItem::Replaced(
-                e.subst_shift(var, val),
-                t.subst_shift(var, val),
-            ),
+            CtxItem::Replaced(e) => CtxItem::Replaced(e.subst_shift(var, val)),
             CtxItem::Kept(v, t) => match v.shift(-1, var) {
-                None => {
-                    CtxItem::Replaced(val.to_value(), t.subst_shift(var, val))
-                }
+                None => CtxItem::Replaced(val.clone()),
                 Some(newvar) => CtxItem::Kept(newvar, t.subst_shift(var, val)),
             },
         }
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index f4cb6b6..c4e3831 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::cell::{Ref, RefCell, RefMut};
 use std::rc::Rc;
 
-use dhall_syntax::{Const, ExprF};
+use dhall_syntax::Const;
 
 use crate::core::context::TypecheckContext;
 use crate::core::valuef::ValueF;
@@ -10,7 +10,7 @@ use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::normalize::{apply_any, normalize_whnf, OutputSubExpr};
 use crate::phase::typecheck::type_of_const;
-use crate::phase::{Normalized, NormalizedSubExpr, Typed};
+use crate::phase::{NormalizedSubExpr, Typed};
 
 #[derive(Debug, Clone, Copy)]
 enum Form {
@@ -28,7 +28,7 @@ enum Form {
 }
 use Form::{Unevaled, NF, WHNF};
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 /// Partially normalized value.
 /// Invariant: if `form` is `WHNF`, `value` must be in Weak Head Normal Form
 /// Invariant: if `form` is `NF`, `value` must be fully normalized
@@ -108,7 +108,7 @@ impl ValueInternal {
 }
 
 impl Value {
-    pub(crate) fn from_valuef(v: ValueF) -> Value {
+    pub(crate) fn from_valuef_untyped(v: ValueF) -> Value {
         ValueInternal {
             form: Unevaled,
             value: v,
@@ -124,18 +124,8 @@ impl Value {
         }
         .into_value()
     }
-    pub(crate) fn from_partial_expr(e: ExprF<Value, Normalized>) -> Value {
-        Value::from_valuef(ValueF::PartialExpr(e))
-    }
-    // TODO: avoid using this function
-    pub(crate) fn with_type(self, t: TypedValue) -> Value {
-        let vint = self.as_internal();
-        ValueInternal {
-            form: vint.form,
-            value: vint.value.clone(),
-            ty: Some(t),
-        }
-        .into_value()
+    pub(crate) fn from_valuef_simple_type(v: ValueF) -> Value {
+        Value::from_valuef_and_type(v, TypedValue::from_const(Const::Type))
     }
 
     /// Mutates the contents. If no one else shares this thunk,
@@ -214,7 +204,7 @@ impl Value {
     }
 
     pub(crate) fn app_valuef(&self, val: ValueF) -> ValueF {
-        self.app_value(val.into_value())
+        self.app_value(val.into_value_untyped())
     }
 
     pub(crate) fn app_value(&self, th: Value) -> ValueF {
@@ -227,41 +217,39 @@ impl Value {
 }
 
 impl TypedValue {
-    pub(crate) fn from_valuef(v: ValueF) -> TypedValue {
-        TypedValue::from_value_untyped(Value::from_valuef(v))
-    }
-
-    pub(crate) fn normalize_nf(&self) -> ValueF {
-        self.0.normalize_nf().clone()
-    }
-
-    pub(crate) fn normalize_to_expr_maybe_alpha(
-        &self,
-        alpha: bool,
-    ) -> OutputSubExpr {
-        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
+    pub fn from_value(th: Value) -> Self {
+        TypedValue(th)
     }
-
-    pub(crate) fn from_value_and_type(th: Value, t: TypedValue) -> Self {
-        TypedValue(th.with_type(t))
+    pub(crate) fn from_valuef_untyped(v: ValueF) -> TypedValue {
+        TypedValue::from_value(Value::from_valuef_untyped(v))
     }
-    pub fn from_value_simple_type(th: Value) -> Self {
-        TypedValue::from_value_and_type(th, TypedValue::const_type())
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: TypedValue) -> Self {
+        TypedValue(Value::from_valuef_and_type(v, t))
     }
-    pub(crate) fn from_value_untyped(th: Value) -> Self {
-        TypedValue(th)
+    // TODO: do something with the info that the type is Type. Maybe check
+    // is a type is present ?
+    pub(crate) fn from_value_simple_type(th: Value) -> Self {
+        TypedValue::from_value(th)
     }
     pub(crate) fn from_const(c: Const) -> Self {
         match type_of_const(c) {
             Ok(t) => TypedValue::from_valuef_and_type(ValueF::Const(c), t),
-            Err(_) => TypedValue::from_valuef(ValueF::Const(c)),
+            Err(_) => TypedValue::from_valuef_untyped(ValueF::Const(c)),
         }
     }
     pub fn const_type() -> Self {
         TypedValue::from_const(Const::Type)
     }
-    pub(crate) fn from_valuef_and_type(v: ValueF, t: TypedValue) -> Self {
-        TypedValue(Value::from_valuef_and_type(v, t))
+
+    pub(crate) fn normalize_nf(&self) -> ValueF {
+        self.0.normalize_nf().clone()
+    }
+
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
+        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
     /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index b948eb1..de55d2f 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -48,8 +48,14 @@ pub enum ValueF {
 }
 
 impl ValueF {
-    pub(crate) fn into_value(self) -> Value {
-        Value::from_valuef(self)
+    pub(crate) fn into_value_untyped(self) -> Value {
+        Value::from_valuef_untyped(self)
+    }
+    pub(crate) fn into_value_with_type(self, t: TypedValue) -> Value {
+        Value::from_valuef_and_type(self, t)
+    }
+    pub(crate) fn into_value_simple_type(self) -> Value {
+        Value::from_valuef_simple_type(self)
     }
 
     /// Convert the value to a fully normalized syntactic expression
@@ -258,12 +264,12 @@ impl ValueF {
 
     /// Apply to a value
     pub(crate) fn app_valuef(self, val: ValueF) -> ValueF {
-        self.app_value(val.into_value())
+        self.app_value(val.into_value_untyped())
     }
 
     /// Apply to a thunk
     pub fn app_value(self, th: Value) -> ValueF {
-        Value::from_valuef(self).app_value(th)
+        Value::from_valuef_untyped(self).app_value(th)
     }
 
     pub fn from_builtin(b: Builtin) -> ValueF {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index dabfe87..27858d8 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -20,7 +20,7 @@ macro_rules! make_closure {
             Label::from(stringify!($var)).into(),
             $n
         );
-        ValueF::Var(var).into_value()
+        ValueF::Var(var).into_value_untyped()
     }};
     // Warning: assumes that $ty, as a dhall value, has type `Type`
     (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
@@ -30,30 +30,40 @@ macro_rules! make_closure {
                 make_closure!($($ty)*),
             ),
             make_closure!($($rest)*),
-        ).into_value()
+        ).into_value_untyped()
+    };
+    (Natural) => {
+        ValueF::from_builtin(Builtin::Natural)
+            .into_value_simple_type()
     };
-    (Natural) => { ValueF::from_builtin(Builtin::Natural).into_value() };
     (List $($rest:tt)*) => {
         ValueF::from_builtin(Builtin::List)
             .app_value(make_closure!($($rest)*))
-            .into_value()
+            .into_value_simple_type()
     };
-    (Some $($rest:tt)*) => {
-        ValueF::NEOptionalLit(make_closure!($($rest)*)).into_value()
+    (Some($($rest:tt)*)) => {
+        ValueF::NEOptionalLit(make_closure!($($rest)*))
+            .into_value_untyped()
     };
     (1 + $($rest:tt)*) => {
         ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::NaturalPlus,
             make_closure!($($rest)*),
-            Value::from_valuef(ValueF::NaturalLit(1)),
-        )).into_value()
+            Value::from_valuef_and_type(
+                ValueF::NaturalLit(1),
+                TypedValue::from_value(make_closure!(Natural))
+            ),
+        )).into_value_with_type(
+            TypedValue::from_value(make_closure!(Natural))
+        )
     };
     ([ $($head:tt)* ] # $($tail:tt)*) => {
         ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::ListAppend,
-            ValueF::NEListLit(vec![make_closure!($($head)*)]).into_value(),
+            ValueF::NEListLit(vec![make_closure!($($head)*)])
+                .into_value_untyped(),
             make_closure!($($tail)*),
-        )).into_value()
+        )).into_value_untyped()
     };
 }
 
@@ -189,10 +199,17 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 let mut kts = HashMap::new();
                 kts.insert(
                     "index".into(),
-                    TypedValue::from_valuef(ValueF::from_builtin(Natural)),
+                    TypedValue::from_valuef_untyped(ValueF::from_builtin(
+                        Natural,
+                    )),
                 );
                 kts.insert("value".into(), t.clone());
-                Ok((r, EmptyListLit(TypedValue::from_valuef(RecordType(kts)))))
+                Ok((
+                    r,
+                    EmptyListLit(TypedValue::from_valuef_untyped(RecordType(
+                        kts,
+                    ))),
+                ))
             }
             NEListLit(xs) => {
                 let xs = xs
@@ -201,9 +218,12 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     .map(|(i, e)| {
                         let i = NaturalLit(i);
                         let mut kvs = HashMap::new();
-                        kvs.insert("index".into(), Value::from_valuef(i));
+                        kvs.insert(
+                            "index".into(),
+                            Value::from_valuef_untyped(i),
+                        );
                         kvs.insert("value".into(), e.clone());
-                        Value::from_valuef(RecordLit(kvs))
+                        Value::from_valuef_untyped(RecordLit(kvs))
                     })
                     .collect();
                 Ok((r, NEListLit(xs)))
@@ -246,7 +266,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                         .clone()
                         .app_value(x.clone())
                         .app_value(v)
-                        .into_value();
+                        .into_value_untyped();
                 }
                 Ok((r, v.to_whnf()))
             }
@@ -267,7 +287,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 f.app_valuef(
                     ValueF::from_builtin(Optional).app_value(t.clone()),
                 )
-                .app_value(make_closure!(λ(x: #t) -> Some var(x, 0)))
+                .app_value(make_closure!(λ(x: #t) -> Some(var(x, 0))))
                 .app_valuef(EmptyOptionalLit(
                     TypedValue::from_value_simple_type(t.clone()),
                 )),
@@ -327,7 +347,7 @@ pub(crate) fn apply_any(f: Value, a: Value) -> ValueF {
     let f_borrow = f.as_whnf();
     match &*f_borrow {
         ValueF::Lam(x, _, e) => {
-            let val = TypedValue::from_value_untyped(a);
+            let val = TypedValue::from_value(a);
             e.subst_shift(&x.into(), &val).to_whnf()
         }
         ValueF::AppliedBuiltin(b, args) => {
@@ -602,11 +622,11 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
         }
         (RecursiveRecordMerge, RecordLit(kvs1), RecordLit(kvs2)) => {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
-                Value::from_partial_expr(ExprF::BinOp(
+                Value::from_valuef_untyped(ValueF::PartialExpr(ExprF::BinOp(
                     RecursiveRecordMerge,
                     v1.clone(),
                     v2.clone(),
-                ))
+                )))
             });
             Ret::ValueF(RecordLit(kvs))
         }
@@ -619,7 +639,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
         }
         (RecursiveRecordTypeMerge, RecordType(kvs1), RecordType(kvs2)) => {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
-                TypedValue::from_value_untyped(Value::from_partial_expr(
+                TypedValue::from_valuef_untyped(ValueF::PartialExpr(
                     ExprF::BinOp(
                         RecursiveRecordTypeMerge,
                         v1.to_value(),
@@ -655,15 +675,15 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         ExprF::Annot(x, _) => Ret::Value(x),
         ExprF::Assert(_) => Ret::Expr(expr),
         ExprF::Lam(x, t, e) => {
-            Ret::ValueF(Lam(x.into(), TypedValue::from_value_untyped(t), e))
+            Ret::ValueF(Lam(x.into(), TypedValue::from_value(t), e))
         }
         ExprF::Pi(x, t, e) => Ret::ValueF(Pi(
             x.into(),
-            TypedValue::from_value_untyped(t),
-            TypedValue::from_value_untyped(e),
+            TypedValue::from_value(t),
+            TypedValue::from_value(e),
         )),
         ExprF::Let(x, _, v, b) => {
-            let v = TypedValue::from_value_untyped(v);
+            let v = TypedValue::from_value(v);
             Ret::Value(b.subst_shift(&x.into(), &v))
         }
         ExprF::App(v, a) => Ret::ValueF(v.app_value(a)),
@@ -697,12 +717,12 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         }
         ExprF::RecordType(kts) => Ret::ValueF(RecordType(
             kts.into_iter()
-                .map(|(k, t)| (k, TypedValue::from_value_untyped(t)))
+                .map(|(k, t)| (k, TypedValue::from_value(t)))
                 .collect(),
         )),
         ExprF::UnionType(kts) => Ret::ValueF(UnionType(
             kts.into_iter()
-                .map(|(k, t)| (k, t.map(|t| TypedValue::from_value_untyped(t))))
+                .map(|(k, t)| (k, t.map(|t| TypedValue::from_value(t))))
                 .collect(),
         )),
         ExprF::TextLit(elts) => {
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 07c4ad8..e24f5a3 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
 };
 
 use crate::core::context::TypecheckContext;
-use crate::core::value::{TypedValue, Value};
+use crate::core::value::TypedValue;
 use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
@@ -37,8 +37,8 @@ fn tck_pi_type(
 
     let k = function_check(ka, kb);
 
-    Ok(TypedValue::from_value_and_type(
-        ValueF::Pi(x.into(), tx, te).into_value(),
+    Ok(TypedValue::from_valuef_and_type(
+        ValueF::Pi(x.into(), tx, te),
         TypedValue::from_const(k),
     ))
 }
@@ -70,8 +70,8 @@ fn tck_record_type(
     // An empty record type has type Type
     let k = k.unwrap_or(Const::Type);
 
-    Ok(TypedValue::from_value_and_type(
-        ValueF::RecordType(new_kts).into_value(),
+    Ok(TypedValue::from_valuef_and_type(
+        ValueF::RecordType(new_kts),
         TypedValue::from_const(k),
     ))
 }
@@ -115,8 +115,8 @@ where
     // an union type with only unary variants also has type Type
     let k = k.unwrap_or(Const::Type);
 
-    Ok(TypedValue::from_value_and_type(
-        ValueF::UnionType(new_kts).into_value(),
+    Ok(TypedValue::from_valuef_and_type(
+        ValueF::UnionType(new_kts),
         TypedValue::from_const(k),
     ))
 }
@@ -281,6 +281,7 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
     }
 }
 
+// TODO: this can't fail in practise
 pub(crate) fn builtin_to_type(b: Builtin) -> Result<TypedValue, TypeError> {
     type_with(&TypecheckContext::new(), SubExpr::from_builtin(b))
 }
@@ -351,8 +352,8 @@ fn type_with(
             match ret {
                 RetTypeOnly(typ) => {
                     let expr = expr.map_ref(|typed| typed.to_value());
-                    TypedValue::from_value_and_type(
-                        Value::from_partial_expr(expr),
+                    TypedValue::from_valuef_and_type(
+                        ValueF::PartialExpr(expr),
                         typ,
                     )
                 }
@@ -465,10 +466,9 @@ fn type_last_layer(
                 ));
             }
 
-            Ok(RetTypeOnly(TypedValue::from_value_and_type(
+            Ok(RetTypeOnly(TypedValue::from_valuef_and_type(
                 ValueF::from_builtin(dhall_syntax::Builtin::List)
-                    .app_value(t.to_value())
-                    .into_value(),
+                    .app_value(t.to_value()),
                 TypedValue::from_const(Type),
             )))
         }
@@ -478,10 +478,9 @@ fn type_last_layer(
                 return Err(TypeError::new(ctx, InvalidOptionalType(t)));
             }
 
-            Ok(RetTypeOnly(TypedValue::from_value_and_type(
+            Ok(RetTypeOnly(TypedValue::from_valuef_and_type(
                 ValueF::from_builtin(dhall_syntax::Builtin::Optional)
-                    .app_value(t.to_value())
-                    .into_value(),
+                    .app_value(t.to_value()),
                 TypedValue::from_const(Type),
             )))
         }
@@ -942,8 +941,8 @@ fn type_last_layer(
                 };
             }
 
-            Ok(RetTypeOnly(TypedValue::from_value_and_type(
-                ValueF::RecordType(new_kts).into_value(),
+            Ok(RetTypeOnly(TypedValue::from_valuef_and_type(
+                ValueF::RecordType(new_kts),
                 record_type.get_type()?.into_owned(),
             )))
         }
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 31643d0..9d2ec85 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -186,7 +186,7 @@ pub mod value {
         ) -> Self {
             Self::make_simple_type(DhallValue::RecordType(
                 kts.map(|(k, t)| {
-                    (k.into(), TypedThunk::from_value_simple_type(t.to_value()))
+                    (k.into(), TypedThunk::from_value(t.to_value()))
                 })
                 .collect(),
             ))
@@ -197,12 +197,7 @@ pub mod value {
         ) -> Self {
             Self::make_simple_type(DhallValue::UnionType(
                 kts.map(|(k, t)| {
-                    (
-                        k.into(),
-                        t.map(|t| {
-                            TypedThunk::from_value_simple_type(t.to_value())
-                        }),
-                    )
+                    (k.into(), t.map(|t| TypedThunk::from_value(t.to_value())))
                 })
                 .collect(),
             ))
-- 
cgit v1.3.1


From 730f2ebb146792994c7492b6c05f7d09d42cbccf Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 19 Aug 2019 23:00:49 +0200
Subject: Merge TypedValue and Value

---
 dhall/src/core/context.rs    |  31 +++----
 dhall/src/core/value.rs      | 192 ++++++++++++++-----------------------------
 dhall/src/core/valuef.rs     |  26 +++---
 dhall/src/error/mod.rs       |  54 ++++++------
 dhall/src/phase/mod.rs       |  16 ++--
 dhall/src/phase/normalize.rs |  90 +++++++-------------
 dhall/src/phase/typecheck.rs | 177 ++++++++++++++++++---------------------
 serde_dhall/src/lib.rs       |  31 +++----
 8 files changed, 245 insertions(+), 372 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs
index deabe44..2bf39c5 100644
--- a/dhall/src/core/context.rs
+++ b/dhall/src/core/context.rs
@@ -3,15 +3,15 @@ use std::rc::Rc;
 
 use dhall_syntax::{Label, V};
 
-use crate::core::value::TypedValue;
+use crate::core::value::Value;
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::TypeError;
 
 #[derive(Debug, Clone)]
 enum CtxItem {
-    Kept(AlphaVar, TypedValue),
-    Replaced(TypedValue),
+    Kept(AlphaVar, Value),
+    Replaced(Value),
 }
 
 #[derive(Debug, Clone)]
@@ -21,21 +21,17 @@ impl TypecheckContext {
     pub fn new() -> Self {
         TypecheckContext(Rc::new(Vec::new()))
     }
-    pub fn insert_type(&self, x: &Label, t: TypedValue) -> Self {
+    pub fn insert_type(&self, x: &Label, t: Value) -> Self {
         let mut vec = self.0.as_ref().clone();
         vec.push((x.clone(), CtxItem::Kept(x.into(), t.under_binder(x))));
         TypecheckContext(Rc::new(vec))
     }
-    pub fn insert_value(
-        &self,
-        x: &Label,
-        e: TypedValue,
-    ) -> Result<Self, TypeError> {
+    pub fn insert_value(&self, x: &Label, e: Value) -> Result<Self, TypeError> {
         let mut vec = self.0.as_ref().clone();
         vec.push((x.clone(), CtxItem::Replaced(e)));
         Ok(TypecheckContext(Rc::new(vec)))
     }
-    pub fn lookup(&self, var: &V<Label>) -> Option<TypedValue> {
+    pub fn lookup(&self, var: &V<Label>) -> Option<Value> {
         let mut var = var.clone();
         let mut shift_map: HashMap<Label, _> = HashMap::new();
         for (l, i) in self.0.iter().rev() {
@@ -44,10 +40,7 @@ impl TypecheckContext {
                     let i = i.under_multiple_binders(&shift_map);
                     return Some(match i {
                         CtxItem::Kept(newvar, t) => {
-                            TypedValue::from_valuef_and_type(
-                                ValueF::Var(newvar),
-                                t,
-                            )
+                            Value::from_valuef_and_type(ValueF::Var(newvar), t)
                         }
                         CtxItem::Replaced(v) => v,
                     });
@@ -101,7 +94,7 @@ impl TypecheckContext {
             )))
         }
     }
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
+    fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
         self.do_with_var(var, |var, i| Ok::<_, !>(i.subst_shift(&var, val)))
             .unwrap()
     }
@@ -124,8 +117,8 @@ impl Shift for TypecheckContext {
     }
 }
 
-impl Subst<TypedValue> for CtxItem {
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
+impl Subst<Value> for CtxItem {
+    fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
         match self {
             CtxItem::Replaced(e) => CtxItem::Replaced(e.subst_shift(var, val)),
             CtxItem::Kept(v, t) => match v.shift(-1, var) {
@@ -136,8 +129,8 @@ impl Subst<TypedValue> for CtxItem {
     }
 }
 
-impl Subst<TypedValue> for TypecheckContext {
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
+impl Subst<Value> for TypecheckContext {
+    fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
         self.subst_shift(var, val)
     }
 }
diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index c4e3831..8573d11 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -35,7 +35,7 @@ use Form::{Unevaled, NF, WHNF};
 struct ValueInternal {
     form: Form,
     value: ValueF,
-    ty: Option<TypedValue>,
+    ty: Option<Value>,
 }
 
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
@@ -45,11 +45,6 @@ struct ValueInternal {
 #[derive(Clone)]
 pub struct Value(Rc<RefCell<ValueInternal>>);
 
-/// A value that needs to carry a type for typechecking to work.
-/// TODO: actually enforce this.
-#[derive(Debug, Clone)]
-pub struct TypedValue(Value);
-
 impl ValueInternal {
     fn into_value(self) -> Value {
         Value(Rc::new(RefCell::new(self)))
@@ -96,7 +91,7 @@ impl ValueInternal {
         }
     }
 
-    fn get_type(&self) -> Result<&TypedValue, TypeError> {
+    fn get_type(&self) -> Result<&Value, TypeError> {
         match &self.ty {
             Some(t) => Ok(t),
             None => Err(TypeError::new(
@@ -116,7 +111,7 @@ impl Value {
         }
         .into_value()
     }
-    pub(crate) fn from_valuef_and_type(v: ValueF, t: TypedValue) -> Value {
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: Value) -> Value {
         ValueInternal {
             form: Unevaled,
             value: v,
@@ -125,7 +120,57 @@ impl Value {
         .into_value()
     }
     pub(crate) fn from_valuef_simple_type(v: ValueF) -> Value {
-        Value::from_valuef_and_type(v, TypedValue::from_const(Const::Type))
+        Value::from_valuef_and_type(v, Value::from_const(Const::Type))
+    }
+    pub(crate) fn from_const(c: Const) -> Self {
+        match type_of_const(c) {
+            Ok(t) => Value::from_valuef_and_type(ValueF::Const(c), t),
+            Err(_) => Value::from_valuef_untyped(ValueF::Const(c)),
+        }
+    }
+    pub fn const_type() -> Self {
+        Value::from_const(Const::Type)
+    }
+
+    pub(crate) fn as_const(&self) -> Option<Const> {
+        match &*self.as_whnf() {
+            ValueF::Const(c) => Some(*c),
+            _ => None,
+        }
+    }
+
+    fn as_internal(&self) -> Ref<ValueInternal> {
+        self.0.borrow()
+    }
+    fn as_internal_mut(&self) -> RefMut<ValueInternal> {
+        self.0.borrow_mut()
+    }
+    /// This is what you want if you want to pattern-match on the value.
+    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
+    /// panics.
+    pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
+        self.do_normalize_whnf();
+        Ref::map(self.as_internal(), ValueInternal::as_whnf)
+    }
+
+    // TODO: rename `normalize_to_expr`
+    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
+        self.as_whnf().normalize_to_expr()
+    }
+    // TODO: rename `normalize_to_expr_maybe_alpha`
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
+        self.as_whnf().normalize_to_expr_maybe_alpha(true)
+    }
+    // TODO: deprecated
+    pub(crate) fn to_value(&self) -> Value {
+        self.clone()
+    }
+    /// TODO: cloning a valuef can often be avoided
+    pub(crate) fn to_whnf(&self) -> ValueF {
+        self.as_whnf().clone()
+    }
+    pub(crate) fn into_typed(self) -> Typed {
+        Typed::from_value(self)
     }
 
     /// Mutates the contents. If no one else shares this thunk,
@@ -138,20 +183,12 @@ impl Value {
             None => f(&mut self.as_internal_mut()),
         }
     }
-
     /// Normalizes contents to normal form; faster than `normalize_nf` if
     /// no one else shares this thunk.
     pub(crate) fn normalize_mut(&mut self) {
         self.mutate_internal(|vint| vint.normalize_nf())
     }
 
-    fn as_internal(&self) -> Ref<ValueInternal> {
-        self.0.borrow()
-    }
-    fn as_internal_mut(&self) -> RefMut<ValueInternal> {
-        self.0.borrow_mut()
-    }
-
     fn do_normalize_whnf(&self) {
         let borrow = self.as_internal();
         match borrow.form {
@@ -163,7 +200,6 @@ impl Value {
             WHNF | NF => {}
         }
     }
-
     fn do_normalize_nf(&self) {
         let borrow = self.as_internal();
         match borrow.form {
@@ -176,26 +212,14 @@ impl Value {
         }
     }
 
-    // WARNING: avoid normalizing any thunk while holding on to this ref
-    // or you could run into BorrowMut panics
+    /// WARNING: avoid normalizing any thunk while holding on to this ref
+    /// or you could run into BorrowMut panics
+    // TODO: rename to `as_nf`
     pub(crate) fn normalize_nf(&self) -> Ref<ValueF> {
         self.do_normalize_nf();
         Ref::map(self.as_internal(), ValueInternal::as_nf)
     }
 
-    /// This is what you want if you want to pattern-match on the value.
-    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
-    /// panics.
-    pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
-        self.do_normalize_whnf();
-        Ref::map(self.as_internal(), ValueInternal::as_whnf)
-    }
-
-    /// TODO: cloning a valuef can often be avoided
-    pub(crate) fn to_whnf(&self) -> ValueF {
-        self.as_whnf().clone()
-    }
-
     pub(crate) fn normalize_to_expr_maybe_alpha(
         &self,
         alpha: bool,
@@ -211,83 +235,11 @@ impl Value {
         apply_any(self.clone(), th)
     }
 
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, TypedValue>, TypeError> {
+    pub(crate) fn get_type(&self) -> Result<Cow<'_, Value>, TypeError> {
         Ok(Cow::Owned(self.as_internal().get_type()?.clone()))
     }
 }
 
-impl TypedValue {
-    pub fn from_value(th: Value) -> Self {
-        TypedValue(th)
-    }
-    pub(crate) fn from_valuef_untyped(v: ValueF) -> TypedValue {
-        TypedValue::from_value(Value::from_valuef_untyped(v))
-    }
-    pub(crate) fn from_valuef_and_type(v: ValueF, t: TypedValue) -> Self {
-        TypedValue(Value::from_valuef_and_type(v, t))
-    }
-    // TODO: do something with the info that the type is Type. Maybe check
-    // is a type is present ?
-    pub(crate) fn from_value_simple_type(th: Value) -> Self {
-        TypedValue::from_value(th)
-    }
-    pub(crate) fn from_const(c: Const) -> Self {
-        match type_of_const(c) {
-            Ok(t) => TypedValue::from_valuef_and_type(ValueF::Const(c), t),
-            Err(_) => TypedValue::from_valuef_untyped(ValueF::Const(c)),
-        }
-    }
-    pub fn const_type() -> Self {
-        TypedValue::from_const(Const::Type)
-    }
-
-    pub(crate) fn normalize_nf(&self) -> ValueF {
-        self.0.normalize_nf().clone()
-    }
-
-    pub(crate) fn normalize_to_expr_maybe_alpha(
-        &self,
-        alpha: bool,
-    ) -> OutputSubExpr {
-        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
-    }
-
-    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
-    /// panics.
-    pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
-        self.0.as_whnf()
-    }
-    pub(crate) fn to_whnf(&self) -> ValueF {
-        self.0.to_whnf()
-    }
-    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
-        self.as_whnf().normalize_to_expr()
-    }
-    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
-        self.as_whnf().normalize_to_expr_maybe_alpha(true)
-    }
-    pub(crate) fn to_value(&self) -> Value {
-        self.0.clone()
-    }
-    pub(crate) fn into_typed(self) -> Typed {
-        Typed::from_typedvalue(self)
-    }
-    pub(crate) fn as_const(&self) -> Option<Const> {
-        match &*self.as_whnf() {
-            ValueF::Const(c) => Some(*c),
-            _ => None,
-        }
-    }
-
-    pub(crate) fn normalize_mut(&mut self) {
-        self.0.normalize_mut()
-    }
-
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, TypedValue>, TypeError> {
-        self.0.get_type()
-    }
-}
-
 impl Shift for Value {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(Value(self.0.shift(delta, var)?))
@@ -304,20 +256,14 @@ impl Shift for ValueInternal {
     }
 }
 
-impl Shift for TypedValue {
-    fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
-        Some(TypedValue(self.0.shift(delta, var)?))
-    }
-}
-
-impl Subst<TypedValue> for Value {
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
+impl Subst<Value> for Value {
+    fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
         Value(self.0.subst_shift(var, val))
     }
 }
 
-impl Subst<TypedValue> for ValueInternal {
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
+impl Subst<Value> for ValueInternal {
+    fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
         ValueInternal {
             // The resulting value may not stay in wnhf after substitution
             form: Unevaled,
@@ -327,12 +273,7 @@ impl Subst<TypedValue> for ValueInternal {
     }
 }
 
-impl Subst<TypedValue> for TypedValue {
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
-        TypedValue(self.0.subst_shift(var, val))
-    }
-}
-
+// TODO: use Rc comparison to shortcut on identical pointers
 impl std::cmp::PartialEq for Value {
     fn eq(&self, other: &Self) -> bool {
         *self.as_whnf() == *other.as_whnf()
@@ -340,13 +281,6 @@ impl std::cmp::PartialEq for Value {
 }
 impl std::cmp::Eq for Value {}
 
-impl std::cmp::PartialEq for TypedValue {
-    fn eq(&self, other: &Self) -> bool {
-        &*self.as_whnf() == &*other.as_whnf()
-    }
-}
-impl std::cmp::Eq for TypedValue {}
-
 impl std::fmt::Debug for Value {
     fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let vint: &ValueInternal = &self.as_internal();
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index de55d2f..0d2655e 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble, Natural,
 };
 
-use crate::core::value::{TypedValue, Value};
+use crate::core::value::Value;
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::normalize::OutputSubExpr;
 use crate::phase::Normalized;
@@ -18,8 +18,8 @@ use crate::phase::Normalized;
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ValueF {
     /// Closures
-    Lam(AlphaLabel, TypedValue, Value),
-    Pi(AlphaLabel, TypedValue, TypedValue),
+    Lam(AlphaLabel, Value, Value),
+    Pi(AlphaLabel, Value, Value),
     // Invariant: the evaluation must not be able to progress further.
     AppliedBuiltin(Builtin, Vec<Value>),
 
@@ -29,20 +29,20 @@ pub enum ValueF {
     NaturalLit(Natural),
     IntegerLit(Integer),
     DoubleLit(NaiveDouble),
-    EmptyOptionalLit(TypedValue),
+    EmptyOptionalLit(Value),
     NEOptionalLit(Value),
     // EmptyListLit(t) means `[] : List t`, not `[] : t`
-    EmptyListLit(TypedValue),
+    EmptyListLit(Value),
     NEListLit(Vec<Value>),
     RecordLit(HashMap<Label, Value>),
-    RecordType(HashMap<Label, TypedValue>),
-    UnionType(HashMap<Label, Option<TypedValue>>),
-    UnionConstructor(Label, HashMap<Label, Option<TypedValue>>),
-    UnionLit(Label, Value, HashMap<Label, Option<TypedValue>>),
+    RecordType(HashMap<Label, Value>),
+    UnionType(HashMap<Label, Option<Value>>),
+    UnionConstructor(Label, HashMap<Label, Option<Value>>),
+    UnionLit(Label, Value, HashMap<Label, Option<Value>>),
     // Invariant: this must not contain interpolations that are themselves TextLits, and
     // contiguous text values must be merged.
     TextLit(Vec<InterpolatedTextContents<Value>>),
-    Equivalence(TypedValue, TypedValue),
+    Equivalence(Value, Value),
     // Invariant: this must not contain a value captured by one of the variants above.
     PartialExpr(ExprF<Value, Normalized>),
 }
@@ -51,7 +51,7 @@ impl ValueF {
     pub(crate) fn into_value_untyped(self) -> Value {
         Value::from_valuef_untyped(self)
     }
-    pub(crate) fn into_value_with_type(self, t: TypedValue) -> Value {
+    pub(crate) fn into_value_with_type(self, t: Value) -> Value {
         Value::from_valuef_and_type(self, t)
     }
     pub(crate) fn into_value_simple_type(self) -> Value {
@@ -333,8 +333,8 @@ impl Shift for ValueF {
     }
 }
 
-impl Subst<TypedValue> for ValueF {
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
+impl Subst<Value> for ValueF {
+    fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
         match self {
             ValueF::AppliedBuiltin(b, args) => {
                 ValueF::AppliedBuiltin(*b, args.subst_shift(var, val))
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 0f2f5fc..b34c3a2 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -3,7 +3,7 @@ use std::io::Error as IOError;
 use dhall_syntax::{BinOp, Import, Label, ParseError, V};
 
 use crate::core::context::TypecheckContext;
-use crate::core::value::TypedValue;
+use crate::core::value::Value;
 use crate::phase::resolve::ImportStack;
 use crate::phase::NormalizedSubExpr;
 
@@ -49,28 +49,28 @@ pub struct TypeError {
 #[derive(Debug)]
 pub(crate) enum TypeMessage {
     UnboundVariable(V<Label>),
-    InvalidInputType(TypedValue),
-    InvalidOutputType(TypedValue),
-    NotAFunction(TypedValue),
-    TypeMismatch(TypedValue, TypedValue, TypedValue),
-    AnnotMismatch(TypedValue, TypedValue),
+    InvalidInputType(Value),
+    InvalidOutputType(Value),
+    NotAFunction(Value),
+    TypeMismatch(Value, Value, Value),
+    AnnotMismatch(Value, Value),
     Untyped,
     FieldCollision(Label),
-    InvalidListElement(usize, TypedValue, TypedValue),
-    InvalidListType(TypedValue),
-    InvalidOptionalType(TypedValue),
-    InvalidPredicate(TypedValue),
-    IfBranchMismatch(TypedValue, TypedValue),
-    IfBranchMustBeTerm(bool, TypedValue),
-    InvalidFieldType(Label, TypedValue),
-    NotARecord(Label, TypedValue),
-    MustCombineRecord(TypedValue),
-    MissingRecordField(Label, TypedValue),
-    MissingUnionField(Label, TypedValue),
-    BinOpTypeMismatch(BinOp, TypedValue),
-    InvalidTextInterpolation(TypedValue),
-    Merge1ArgMustBeRecord(TypedValue),
-    Merge2ArgMustBeUnion(TypedValue),
+    InvalidListElement(usize, Value, Value),
+    InvalidListType(Value),
+    InvalidOptionalType(Value),
+    InvalidPredicate(Value),
+    IfBranchMismatch(Value, Value),
+    IfBranchMustBeTerm(bool, Value),
+    InvalidFieldType(Label, Value),
+    NotARecord(Label, Value),
+    MustCombineRecord(Value),
+    MissingRecordField(Label, Value),
+    MissingUnionField(Label, Value),
+    BinOpTypeMismatch(BinOp, Value),
+    InvalidTextInterpolation(Value),
+    Merge1ArgMustBeRecord(Value),
+    Merge2ArgMustBeUnion(Value),
     MergeEmptyNeedsAnnotation,
     MergeHandlerMissingVariant(Label),
     MergeVariantMissingHandler(Label),
@@ -80,14 +80,14 @@ pub(crate) enum TypeMessage {
     ProjectionMustBeRecord,
     ProjectionMissingEntry,
     Sort,
-    RecordMismatch(TypedValue, TypedValue),
+    RecordMismatch(Value, Value),
     RecordTypeDuplicateField,
-    RecordTypeMergeRequiresRecordType(TypedValue),
-    RecordTypeMismatch(TypedValue, TypedValue, TypedValue, TypedValue),
+    RecordTypeMergeRequiresRecordType(Value),
+    RecordTypeMismatch(Value, Value, Value, Value),
     UnionTypeDuplicateField,
-    EquivalenceArgumentMustBeTerm(bool, TypedValue),
-    EquivalenceTypeMismatch(TypedValue, TypedValue),
-    AssertMismatch(TypedValue, TypedValue),
+    EquivalenceArgumentMustBeTerm(bool, Value),
+    EquivalenceTypeMismatch(Value, Value),
+    AssertMismatch(Value, Value),
     AssertMustTakeEquivalence,
 }
 
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index e58e689..91d64c3 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -4,7 +4,7 @@ use std::path::Path;
 
 use dhall_syntax::{Const, SubExpr};
 
-use crate::core::value::{TypedValue, Value};
+use crate::core::value::Value;
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{EncodeError, Error, ImportError, TypeError};
@@ -33,7 +33,7 @@ pub struct Resolved(ResolvedSubExpr);
 
 /// A typed expression
 #[derive(Debug, Clone)]
-pub struct Typed(TypedValue);
+pub struct Typed(Value);
 
 /// A normalized expression.
 ///
@@ -91,12 +91,12 @@ impl Typed {
     }
 
     pub(crate) fn from_const(c: Const) -> Self {
-        Typed(TypedValue::from_const(c))
+        Typed(Value::from_const(c))
     }
     pub fn from_valuef_and_type(v: ValueF, t: Typed) -> Self {
-        Typed(TypedValue::from_valuef_and_type(v, t.into_typedvalue()))
+        Typed(Value::from_valuef_and_type(v, t.into_value()))
     }
-    pub(crate) fn from_typedvalue(th: TypedValue) -> Self {
+    pub(crate) fn from_value(th: Value) -> Self {
         Typed(th)
     }
     pub fn const_type() -> Self {
@@ -112,7 +112,7 @@ impl Typed {
     pub fn to_value(&self) -> Value {
         self.0.to_value()
     }
-    pub(crate) fn into_typedvalue(self) -> TypedValue {
+    pub(crate) fn into_value(self) -> Value {
         self.0
     }
 
@@ -155,8 +155,8 @@ impl Shift for Normalized {
     }
 }
 
-impl Subst<TypedValue> for Typed {
-    fn subst_shift(&self, var: &AlphaVar, val: &TypedValue) -> Self {
+impl Subst<Value> for Typed {
+    fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
         Typed(self.0.subst_shift(var, val))
     }
 }
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 27858d8..821c5fd 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble,
 };
 
-use crate::core::value::{TypedValue, Value};
+use crate::core::value::Value;
 use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr};
@@ -26,9 +26,7 @@ macro_rules! make_closure {
     (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
         ValueF::Lam(
             Label::from(stringify!($var)).into(),
-            TypedValue::from_value_simple_type(
-                make_closure!($($ty)*),
-            ),
+            make_closure!($($ty)*),
             make_closure!($($rest)*),
         ).into_value_untyped()
     };
@@ -51,10 +49,10 @@ macro_rules! make_closure {
             make_closure!($($rest)*),
             Value::from_valuef_and_type(
                 ValueF::NaturalLit(1),
-                TypedValue::from_value(make_closure!(Natural))
+                make_closure!(Natural)
             ),
         )).into_value_with_type(
-            TypedValue::from_value(make_closure!(Natural))
+            make_closure!(Natural)
         )
     };
     ([ $($head:tt)* ] # $($tail:tt)*) => {
@@ -74,10 +72,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
 
     // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
     let ret = match (b, args.as_slice()) {
-        (OptionalNone, [t, r..]) => Ok((
-            r,
-            EmptyOptionalLit(TypedValue::from_value_simple_type(t.clone())),
-        )),
+        (OptionalNone, [t, r..]) => Ok((r, EmptyOptionalLit(t.clone()))),
         (NaturalIsZero, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
             _ => Err(()),
@@ -199,16 +194,12 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 let mut kts = HashMap::new();
                 kts.insert(
                     "index".into(),
-                    TypedValue::from_valuef_untyped(ValueF::from_builtin(
-                        Natural,
-                    )),
+                    Value::from_valuef_untyped(ValueF::from_builtin(Natural)),
                 );
                 kts.insert("value".into(), t.clone());
                 Ok((
                     r,
-                    EmptyListLit(TypedValue::from_valuef_untyped(RecordType(
-                        kts,
-                    ))),
+                    EmptyListLit(Value::from_valuef_untyped(RecordType(kts))),
                 ))
             }
             NEListLit(xs) => {
@@ -252,9 +243,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                             [ var(x, 1) ] # var(xs, 0)
                         )
                     })
-                    .app_valuef(EmptyListLit(
-                        TypedValue::from_value_simple_type(t.clone()),
-                    )),
+                    .app_valuef(EmptyListLit(t.clone())),
             )),
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() {
@@ -288,9 +277,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     ValueF::from_builtin(Optional).app_value(t.clone()),
                 )
                 .app_value(make_closure!(λ(x: #t) -> Some(var(x, 0))))
-                .app_valuef(EmptyOptionalLit(
-                    TypedValue::from_value_simple_type(t.clone()),
-                )),
+                .app_valuef(EmptyOptionalLit(t.clone())),
             )),
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
@@ -346,10 +333,7 @@ pub(crate) fn apply_any(f: Value, a: Value) -> ValueF {
 
     let f_borrow = f.as_whnf();
     match &*f_borrow {
-        ValueF::Lam(x, _, e) => {
-            let val = TypedValue::from_value(a);
-            e.subst_shift(&x.into(), &val).to_whnf()
-        }
+        ValueF::Lam(x, _, e) => e.subst_shift(&x.into(), &a).to_whnf(),
         ValueF::AppliedBuiltin(b, args) => {
             use std::iter::once;
             let args = args.iter().cloned().chain(once(a.clone())).collect();
@@ -639,21 +623,18 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
         }
         (RecursiveRecordTypeMerge, RecordType(kvs1), RecordType(kvs2)) => {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
-                TypedValue::from_valuef_untyped(ValueF::PartialExpr(
-                    ExprF::BinOp(
-                        RecursiveRecordTypeMerge,
-                        v1.to_value(),
-                        v2.to_value(),
-                    ),
-                ))
+                Value::from_valuef_untyped(ValueF::PartialExpr(ExprF::BinOp(
+                    RecursiveRecordTypeMerge,
+                    v1.to_value(),
+                    v2.to_value(),
+                )))
             });
             Ret::ValueF(RecordType(kvs))
         }
 
-        (Equivalence, _, _) => Ret::ValueF(ValueF::Equivalence(
-            TypedValue::from_value_simple_type(x.clone()),
-            TypedValue::from_value_simple_type(y.clone()),
-        )),
+        (Equivalence, _, _) => {
+            Ret::ValueF(ValueF::Equivalence(x.clone(), y.clone()))
+        }
 
         _ => return None,
     })
@@ -674,18 +655,9 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         ExprF::Var(_) => unreachable!(),
         ExprF::Annot(x, _) => Ret::Value(x),
         ExprF::Assert(_) => Ret::Expr(expr),
-        ExprF::Lam(x, t, e) => {
-            Ret::ValueF(Lam(x.into(), TypedValue::from_value(t), e))
-        }
-        ExprF::Pi(x, t, e) => Ret::ValueF(Pi(
-            x.into(),
-            TypedValue::from_value(t),
-            TypedValue::from_value(e),
-        )),
-        ExprF::Let(x, _, v, b) => {
-            let v = TypedValue::from_value(v);
-            Ret::Value(b.subst_shift(&x.into(), &v))
-        }
+        ExprF::Lam(x, t, e) => Ret::ValueF(Lam(x.into(), t, e)),
+        ExprF::Pi(x, t, e) => Ret::ValueF(Pi(x.into(), t, e)),
+        ExprF::Let(x, _, v, b) => Ret::Value(b.subst_shift(&x.into(), &v)),
         ExprF::App(v, a) => Ret::ValueF(v.app_value(a)),
         ExprF::Builtin(b) => Ret::ValueF(ValueF::from_builtin(b)),
         ExprF::Const(c) => Ret::ValueF(ValueF::Const(c)),
@@ -699,9 +671,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
             let t_borrow = t.as_whnf();
             match &*t_borrow {
                 AppliedBuiltin(Builtin::List, args) if args.len() == 1 => {
-                    Ret::ValueF(EmptyListLit(
-                        TypedValue::from_value_simple_type(args[0].clone()),
-                    ))
+                    Ret::ValueF(EmptyListLit(args[0].clone()))
                 }
                 _ => {
                     drop(t_borrow);
@@ -715,16 +685,12 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         ExprF::RecordLit(kvs) => {
             Ret::ValueF(RecordLit(kvs.into_iter().collect()))
         }
-        ExprF::RecordType(kts) => Ret::ValueF(RecordType(
-            kts.into_iter()
-                .map(|(k, t)| (k, TypedValue::from_value(t)))
-                .collect(),
-        )),
-        ExprF::UnionType(kts) => Ret::ValueF(UnionType(
-            kts.into_iter()
-                .map(|(k, t)| (k, t.map(|t| TypedValue::from_value(t))))
-                .collect(),
-        )),
+        ExprF::RecordType(kts) => {
+            Ret::ValueF(RecordType(kts.into_iter().collect()))
+        }
+        ExprF::UnionType(kts) => {
+            Ret::ValueF(UnionType(kts.into_iter().collect()))
+        }
         ExprF::TextLit(elts) => {
             use InterpolatedTextContents::Expr;
             let elts: Vec<_> = squash_textlit(elts.into_iter());
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index e24f5a3..e65881e 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
 };
 
 use crate::core::context::TypecheckContext;
-use crate::core::value::TypedValue;
+use crate::core::value::Value;
 use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
@@ -14,9 +14,9 @@ use crate::phase::Normalized;
 fn tck_pi_type(
     ctx: &TypecheckContext,
     x: Label,
-    tx: TypedValue,
-    te: TypedValue,
-) -> Result<TypedValue, TypeError> {
+    tx: Value,
+    te: Value,
+) -> Result<Value, TypeError> {
     use crate::error::TypeMessage::*;
     let ctx2 = ctx.insert_type(&x, tx.clone());
 
@@ -37,16 +37,16 @@ fn tck_pi_type(
 
     let k = function_check(ka, kb);
 
-    Ok(TypedValue::from_valuef_and_type(
+    Ok(Value::from_valuef_and_type(
         ValueF::Pi(x.into(), tx, te),
-        TypedValue::from_const(k),
+        Value::from_const(k),
     ))
 }
 
 fn tck_record_type(
     ctx: &TypecheckContext,
-    kts: impl IntoIterator<Item = Result<(Label, TypedValue), TypeError>>,
-) -> Result<TypedValue, TypeError> {
+    kts: impl IntoIterator<Item = Result<(Label, Value), TypeError>>,
+) -> Result<Value, TypeError> {
     use crate::error::TypeMessage::*;
     use std::collections::hash_map::Entry;
     let mut new_kts = HashMap::new();
@@ -70,18 +70,18 @@ fn tck_record_type(
     // An empty record type has type Type
     let k = k.unwrap_or(Const::Type);
 
-    Ok(TypedValue::from_valuef_and_type(
+    Ok(Value::from_valuef_and_type(
         ValueF::RecordType(new_kts),
-        TypedValue::from_const(k),
+        Value::from_const(k),
     ))
 }
 
 fn tck_union_type<Iter>(
     ctx: &TypecheckContext,
     kts: Iter,
-) -> Result<TypedValue, TypeError>
+) -> Result<Value, TypeError>
 where
-    Iter: IntoIterator<Item = Result<(Label, Option<TypedValue>), TypeError>>,
+    Iter: IntoIterator<Item = Result<(Label, Option<Value>), TypeError>>,
 {
     use crate::error::TypeMessage::*;
     use std::collections::hash_map::Entry;
@@ -115,9 +115,9 @@ where
     // an union type with only unary variants also has type Type
     let k = k.unwrap_or(Const::Type);
 
-    Ok(TypedValue::from_valuef_and_type(
+    Ok(Value::from_valuef_and_type(
         ValueF::UnionType(new_kts),
-        TypedValue::from_const(k),
+        Value::from_const(k),
     ))
 }
 
@@ -130,10 +130,10 @@ fn function_check(a: Const, b: Const) -> Const {
     }
 }
 
-pub(crate) fn type_of_const(c: Const) -> Result<TypedValue, TypeError> {
+pub(crate) fn type_of_const(c: Const) -> Result<Value, TypeError> {
     match c {
-        Const::Type => Ok(TypedValue::from_const(Const::Kind)),
-        Const::Kind => Ok(TypedValue::from_const(Const::Sort)),
+        Const::Type => Ok(Value::from_const(Const::Kind)),
+        Const::Kind => Ok(Value::from_const(Const::Sort)),
         Const::Sort => {
             Err(TypeError::new(&TypecheckContext::new(), TypeMessage::Sort))
         }
@@ -282,16 +282,16 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
 }
 
 // TODO: this can't fail in practise
-pub(crate) fn builtin_to_type(b: Builtin) -> Result<TypedValue, TypeError> {
+pub(crate) fn builtin_to_type(b: Builtin) -> Result<Value, TypeError> {
     type_with(&TypecheckContext::new(), SubExpr::from_builtin(b))
 }
 
 /// Intermediary return type
 enum Ret {
     /// Returns the contained value as is
-    RetWhole(TypedValue),
-    /// Use the contained TypedValue as the type of the input expression
-    RetTypeOnly(TypedValue),
+    RetWhole(Value),
+    /// Use the contained Value as the type of the input expression
+    RetTypeOnly(Value),
 }
 
 /// Type-check an expression and return the expression alongside its type if type-checking
@@ -301,7 +301,7 @@ enum Ret {
 fn type_with(
     ctx: &TypecheckContext,
     e: SubExpr<Normalized>,
-) -> Result<TypedValue, TypeError> {
+) -> Result<Value, TypeError> {
     use dhall_syntax::ExprF::{Annot, Embed, Lam, Let, Pi, Var};
 
     use Ret::*;
@@ -313,7 +313,7 @@ fn type_with(
             let v = ValueF::Lam(x.clone().into(), tx.clone(), b.to_value());
             let tb = b.get_type()?.into_owned();
             let t = tck_pi_type(ctx, x.clone(), tx, tb)?;
-            TypedValue::from_valuef_and_type(v, t)
+            Value::from_valuef_and_type(v, t)
         }
         Pi(x, ta, tb) => {
             let ta = type_with(ctx, ta.clone())?;
@@ -331,7 +331,7 @@ fn type_with(
             let v = type_with(ctx, v)?;
             return type_with(&ctx.insert_value(x, v.clone())?, e.clone());
         }
-        Embed(p) => p.clone().into_typed().into_typedvalue(),
+        Embed(p) => p.clone().into_typed().into_value(),
         Var(var) => match ctx.lookup(&var) {
             Some(typed) => typed.clone(),
             None => {
@@ -352,10 +352,7 @@ fn type_with(
             match ret {
                 RetTypeOnly(typ) => {
                     let expr = expr.map_ref(|typed| typed.to_value());
-                    TypedValue::from_valuef_and_type(
-                        ValueF::PartialExpr(expr),
-                        typ,
-                    )
+                    Value::from_valuef_and_type(ValueF::PartialExpr(expr), typ)
                 }
                 RetWhole(tt) => tt,
             }
@@ -367,7 +364,7 @@ fn type_with(
 /// layer.
 fn type_last_layer(
     ctx: &TypecheckContext,
-    e: &ExprF<TypedValue, Normalized>,
+    e: &ExprF<Value, Normalized>,
 ) -> Result<Ret, TypeError> {
     use crate::error::TypeMessage::*;
     use dhall_syntax::BinOp::*;
@@ -466,10 +463,10 @@ fn type_last_layer(
                 ));
             }
 
-            Ok(RetTypeOnly(TypedValue::from_valuef_and_type(
+            Ok(RetTypeOnly(Value::from_valuef_and_type(
                 ValueF::from_builtin(dhall_syntax::Builtin::List)
                     .app_value(t.to_value()),
-                TypedValue::from_const(Type),
+                Value::from_const(Type),
             )))
         }
         SomeLit(x) => {
@@ -478,10 +475,10 @@ fn type_last_layer(
                 return Err(TypeError::new(ctx, InvalidOptionalType(t)));
             }
 
-            Ok(RetTypeOnly(TypedValue::from_valuef_and_type(
+            Ok(RetTypeOnly(Value::from_valuef_and_type(
                 ValueF::from_builtin(dhall_syntax::Builtin::Optional)
                     .app_value(t.to_value()),
-                TypedValue::from_const(Type),
+                Value::from_const(Type),
             )))
         }
         RecordType(kts) => Ok(RetWhole(tck_record_type(
@@ -545,7 +542,7 @@ fn type_last_layer(
                 // ))),
             }
         }
-        Const(c) => Ok(RetWhole(TypedValue::from_const(*c))),
+        Const(c) => Ok(RetWhole(Value::from_const(*c))),
         Builtin(b) => Ok(RetTypeOnly(type_with(ctx, rc(type_of_builtin(*b)))?)),
         BoolLit(_) => Ok(RetTypeOnly(builtin_to_type(Bool)?)),
         NaturalLit(_) => Ok(RetTypeOnly(builtin_to_type(Natural)?)),
@@ -607,43 +604,38 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: &HashMap<Label, TypedValue>,
-                kts_r: &HashMap<Label, TypedValue>,
-            ) -> Result<TypedValue, TypeError> {
+                kts_l: &HashMap<Label, Value>,
+                kts_r: &HashMap<Label, Value>,
+            ) -> Result<Value, TypeError> {
                 use crate::phase::normalize::outer_join;
 
                 // If the Label exists for both records and the values
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
-                let combine =
-                    |k: &Label,
-                     inner_l: &TypedValue,
-                     inner_r: &TypedValue|
-                     -> Result<TypedValue, TypeError> {
-                        match (&*inner_l.as_whnf(), &*inner_r.as_whnf()) {
-                            (
-                                ValueF::RecordType(inner_l_kvs),
-                                ValueF::RecordType(inner_r_kvs),
-                            ) => combine_record_types(
-                                ctx,
-                                inner_l_kvs,
-                                inner_r_kvs,
-                            ),
-                            (_, _) => Err(TypeError::new(
-                                ctx,
-                                FieldCollision(k.clone()),
-                            )),
+                let combine = |k: &Label,
+                               inner_l: &Value,
+                               inner_r: &Value|
+                 -> Result<Value, TypeError> {
+                    match (&*inner_l.as_whnf(), &*inner_r.as_whnf()) {
+                        (
+                            ValueF::RecordType(inner_l_kvs),
+                            ValueF::RecordType(inner_r_kvs),
+                        ) => {
+                            combine_record_types(ctx, inner_l_kvs, inner_r_kvs)
                         }
-                    };
+                        (_, _) => {
+                            Err(TypeError::new(ctx, FieldCollision(k.clone())))
+                        }
+                    }
+                };
 
-                let kts: HashMap<Label, Result<TypedValue, TypeError>> =
-                    outer_join(
-                        |l| Ok(l.clone()),
-                        |r| Ok(r.clone()),
-                        combine,
-                        kts_l,
-                        kts_r,
-                    );
+                let kts: HashMap<Label, Result<Value, TypeError>> = outer_join(
+                    |l| Ok(l.clone()),
+                    |r| Ok(r.clone()),
+                    combine,
+                    kts_l,
+                    kts_r,
+                );
 
                 Ok(tck_record_type(
                     ctx,
@@ -684,35 +676,30 @@ fn type_last_layer(
             // records of records when merging.
             fn combine_record_types(
                 ctx: &TypecheckContext,
-                kts_l: &HashMap<Label, TypedValue>,
-                kts_r: &HashMap<Label, TypedValue>,
-            ) -> Result<TypedValue, TypeError> {
+                kts_l: &HashMap<Label, Value>,
+                kts_r: &HashMap<Label, Value>,
+            ) -> Result<Value, TypeError> {
                 use crate::phase::normalize::intersection_with_key;
 
                 // If the Label exists for both records and the values
                 // are records themselves, then we hit the recursive case.
                 // Otherwise we have a field collision.
-                let combine =
-                    |k: &Label,
-                     kts_l_inner: &TypedValue,
-                     kts_r_inner: &TypedValue|
-                     -> Result<TypedValue, TypeError> {
-                        match (&*kts_l_inner.as_whnf(), &*kts_r_inner.as_whnf())
-                        {
-                            (
-                                ValueF::RecordType(kvs_l_inner),
-                                ValueF::RecordType(kvs_r_inner),
-                            ) => combine_record_types(
-                                ctx,
-                                kvs_l_inner,
-                                kvs_r_inner,
-                            ),
-                            (_, _) => Err(TypeError::new(
-                                ctx,
-                                FieldCollision(k.clone()),
-                            )),
+                let combine = |k: &Label,
+                               kts_l_inner: &Value,
+                               kts_r_inner: &Value|
+                 -> Result<Value, TypeError> {
+                    match (&*kts_l_inner.as_whnf(), &*kts_r_inner.as_whnf()) {
+                        (
+                            ValueF::RecordType(kvs_l_inner),
+                            ValueF::RecordType(kvs_r_inner),
+                        ) => {
+                            combine_record_types(ctx, kvs_l_inner, kvs_r_inner)
                         }
-                    };
+                        (_, _) => {
+                            Err(TypeError::new(ctx, FieldCollision(k.clone())))
+                        }
+                    }
+                };
 
                 let kts = intersection_with_key(combine, kts_l, kts_r);
 
@@ -747,8 +734,8 @@ fn type_last_layer(
                 k_l
             } else {
                 return Err(mkerr(RecordTypeMismatch(
-                    TypedValue::from_const(k_l),
-                    TypedValue::from_const(k_r),
+                    Value::from_const(k_l),
+                    Value::from_const(k_r),
                     l.clone(),
                     r.clone(),
                 )));
@@ -779,7 +766,7 @@ fn type_last_layer(
             // Ensure that the records combine without a type error
             // and if not output the final Const value.
             combine_record_types(ctx, kts_x, kts_y)
-                .and(Ok(RetTypeOnly(TypedValue::from_const(k))))
+                .and(Ok(RetTypeOnly(Value::from_const(k))))
         }
         BinOp(o @ ListAppend, l, r) => {
             match &*l.get_type()?.as_whnf() {
@@ -814,7 +801,7 @@ fn type_last_layer(
                 )));
             }
 
-            Ok(RetTypeOnly(TypedValue::from_const(Type)))
+            Ok(RetTypeOnly(Value::from_const(Type)))
         }
         BinOp(o, l, r) => {
             let t = builtin_to_type(match o {
@@ -941,7 +928,7 @@ fn type_last_layer(
                 };
             }
 
-            Ok(RetTypeOnly(TypedValue::from_valuef_and_type(
+            Ok(RetTypeOnly(Value::from_valuef_and_type(
                 ValueF::RecordType(new_kts),
                 record_type.get_type()?.into_owned(),
             )))
@@ -952,15 +939,13 @@ fn type_last_layer(
 /// `type_of` is the same as `type_with` with an empty context, meaning that the
 /// expression must be closed (i.e. no free variables), otherwise type-checking
 /// will fail.
-pub(crate) fn typecheck(
-    e: SubExpr<Normalized>,
-) -> Result<TypedValue, TypeError> {
+pub(crate) fn typecheck(e: SubExpr<Normalized>) -> Result<Value, TypeError> {
     type_with(&TypecheckContext::new(), e)
 }
 
 pub(crate) fn typecheck_with(
     expr: SubExpr<Normalized>,
     ty: SubExpr<Normalized>,
-) -> Result<TypedValue, TypeError> {
+) -> Result<Value, TypeError> {
     typecheck(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
 }
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 9d2ec85..cef11dd 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -124,9 +124,8 @@ pub use value::Value;
 
 // A Dhall value.
 pub mod value {
-    use dhall::core::value::TypedValue as TypedThunk;
-    use dhall::core::value::Value as Thunk;
-    use dhall::core::valuef::ValueF as DhallValue;
+    use dhall::core::value::Value as DhallValue;
+    use dhall::core::valuef::ValueF as DhallValueF;
     use dhall::phase::{NormalizedSubExpr, Parsed, Typed};
     use dhall_syntax::Builtin;
 
@@ -154,7 +153,7 @@ pub mod value {
         pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
             self.0.to_expr()
         }
-        pub(crate) fn to_value(&self) -> Thunk {
+        pub(crate) fn to_value(&self) -> DhallValue {
             self.0.to_value()
         }
         pub(crate) fn as_typed(&self) -> &Typed {
@@ -162,21 +161,22 @@ pub mod value {
         }
 
         /// Assumes that the given value has type `Type`.
-        pub(crate) fn make_simple_type(v: DhallValue) -> Self {
+        pub(crate) fn make_simple_type(v: DhallValueF) -> Self {
             Value(Typed::from_valuef_and_type(v, Typed::const_type()))
         }
         pub(crate) fn make_builtin_type(b: Builtin) -> Self {
-            Self::make_simple_type(DhallValue::from_builtin(b))
+            Self::make_simple_type(DhallValueF::from_builtin(b))
         }
         pub(crate) fn make_optional_type(t: Value) -> Self {
             Self::make_simple_type(
-                DhallValue::from_builtin(Builtin::Optional)
+                DhallValueF::from_builtin(Builtin::Optional)
                     .app_value(t.to_value()),
             )
         }
         pub(crate) fn make_list_type(t: Value) -> Self {
             Self::make_simple_type(
-                DhallValue::from_builtin(Builtin::List).app_value(t.to_value()),
+                DhallValueF::from_builtin(Builtin::List)
+                    .app_value(t.to_value()),
             )
         }
         // Made public for the StaticType derive macro
@@ -184,22 +184,17 @@ pub mod value {
         pub fn make_record_type(
             kts: impl Iterator<Item = (String, Value)>,
         ) -> Self {
-            Self::make_simple_type(DhallValue::RecordType(
-                kts.map(|(k, t)| {
-                    (k.into(), TypedThunk::from_value(t.to_value()))
-                })
-                .collect(),
+            Self::make_simple_type(DhallValueF::RecordType(
+                kts.map(|(k, t)| (k.into(), t.to_value())).collect(),
             ))
         }
         #[doc(hidden)]
         pub fn make_union_type(
             kts: impl Iterator<Item = (String, Option<Value>)>,
         ) -> Self {
-            Self::make_simple_type(DhallValue::UnionType(
-                kts.map(|(k, t)| {
-                    (k.into(), t.map(|t| TypedThunk::from_value(t.to_value())))
-                })
-                .collect(),
+            Self::make_simple_type(DhallValueF::UnionType(
+                kts.map(|(k, t)| (k.into(), t.map(|t| t.to_value())))
+                    .collect(),
             ))
         }
     }
-- 
cgit v1.3.1


From 88a3b5efb2cf4b8ebb3743389e5666deae5f8962 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 19 Aug 2019 23:09:08 +0200
Subject: Tweak Value API

---
 dhall/src/core/value.rs | 47 +++++++++++++++++++----------------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 8573d11..87816c4 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -49,6 +49,9 @@ impl ValueInternal {
     fn into_value(self) -> Value {
         Value(Rc::new(RefCell::new(self)))
     }
+    fn as_valuef(&self) -> &ValueF {
+        &self.value
+    }
 
     fn normalize_whnf(&mut self) {
         take_mut::take(self, |vint| match &vint.form {
@@ -76,21 +79,6 @@ impl ValueInternal {
         }
     }
 
-    /// Always use normalize_whnf before
-    fn as_whnf(&self) -> &ValueF {
-        match self.form {
-            Unevaled => unreachable!(),
-            _ => &self.value,
-        }
-    }
-    /// Always use normalize_nf before
-    fn as_nf(&self) -> &ValueF {
-        match self.form {
-            Unevaled | WHNF => unreachable!(),
-            NF => &self.value,
-        }
-    }
-
     fn get_type(&self) -> Result<&Value, TypeError> {
         match &self.ty {
             Some(t) => Ok(t),
@@ -145,12 +133,23 @@ impl Value {
     fn as_internal_mut(&self) -> RefMut<ValueInternal> {
         self.0.borrow_mut()
     }
+    /// WARNING: The returned ValueF may be entirely unnormalized, in aprticular it may just be an
+    /// unevaled PartialExpr. You probably want to use `as_whnf`.
+    fn as_valuef(&self) -> Ref<ValueF> {
+        Ref::map(self.as_internal(), ValueInternal::as_valuef)
+    }
     /// This is what you want if you want to pattern-match on the value.
     /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
     /// panics.
     pub(crate) fn as_whnf(&self) -> Ref<ValueF> {
-        self.do_normalize_whnf();
-        Ref::map(self.as_internal(), ValueInternal::as_whnf)
+        self.normalize_whnf();
+        self.as_valuef()
+    }
+    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
+    /// panics.
+    pub(crate) fn as_nf(&self) -> Ref<ValueF> {
+        self.normalize_nf();
+        self.as_valuef()
     }
 
     // TODO: rename `normalize_to_expr`
@@ -189,7 +188,7 @@ impl Value {
         self.mutate_internal(|vint| vint.normalize_nf())
     }
 
-    fn do_normalize_whnf(&self) {
+    pub(crate) fn normalize_whnf(&self) {
         let borrow = self.as_internal();
         match borrow.form {
             Unevaled => {
@@ -200,7 +199,7 @@ impl Value {
             WHNF | NF => {}
         }
     }
-    fn do_normalize_nf(&self) {
+    pub(crate) fn normalize_nf(&self) {
         let borrow = self.as_internal();
         match borrow.form {
             Unevaled | WHNF => {
@@ -212,19 +211,11 @@ impl Value {
         }
     }
 
-    /// WARNING: avoid normalizing any thunk while holding on to this ref
-    /// or you could run into BorrowMut panics
-    // TODO: rename to `as_nf`
-    pub(crate) fn normalize_nf(&self) -> Ref<ValueF> {
-        self.do_normalize_nf();
-        Ref::map(self.as_internal(), ValueInternal::as_nf)
-    }
-
     pub(crate) fn normalize_to_expr_maybe_alpha(
         &self,
         alpha: bool,
     ) -> OutputSubExpr {
-        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
+        self.as_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
     pub(crate) fn app_valuef(&self, val: ValueF) -> ValueF {
-- 
cgit v1.3.1


From caf36246a517b884d7cfcf7c31e1b5d8fce60dfa Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 13:49:13 +0200
Subject: Cleanup

---
 dhall/src/core/value.rs      | 16 ++------
 dhall/src/core/valuef.rs     |  6 +--
 dhall/src/phase/mod.rs       |  2 +-
 dhall/src/phase/normalize.rs | 87 ++++++++++++++++++++++++++++----------------
 dhall/src/phase/typecheck.rs |  6 +--
 5 files changed, 65 insertions(+), 52 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 87816c4..0af7c8c 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -40,8 +40,7 @@ struct ValueInternal {
 
 /// Stores a possibly unevaluated value. Gets (partially) normalized on-demand,
 /// sharing computation automatically. Uses a RefCell to share computation.
-/// Can optionally store a type from typechecking to preserve type information through
-/// normalization.
+/// Can optionally store a type from typechecking to preserve type information.
 #[derive(Clone)]
 pub struct Value(Rc<RefCell<ValueInternal>>);
 
@@ -160,10 +159,6 @@ impl Value {
     pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.as_whnf().normalize_to_expr_maybe_alpha(true)
     }
-    // TODO: deprecated
-    pub(crate) fn to_value(&self) -> Value {
-        self.clone()
-    }
     /// TODO: cloning a valuef can often be avoided
     pub(crate) fn to_whnf(&self) -> ValueF {
         self.as_whnf().clone()
@@ -172,8 +167,7 @@ impl Value {
         Typed::from_value(self)
     }
 
-    /// Mutates the contents. If no one else shares this thunk,
-    /// mutates directly, thus avoiding a RefCell lock.
+    /// Mutates the contents. If no one else shares this, this avoids a RefCell lock.
     fn mutate_internal(&mut self, f: impl FnOnce(&mut ValueInternal)) {
         match Rc::get_mut(&mut self.0) {
             // Mutate directly if sole owner
@@ -183,7 +177,7 @@ impl Value {
         }
     }
     /// Normalizes contents to normal form; faster than `normalize_nf` if
-    /// no one else shares this thunk.
+    /// no one else shares this.
     pub(crate) fn normalize_mut(&mut self) {
         self.mutate_internal(|vint| vint.normalize_nf())
     }
@@ -218,10 +212,6 @@ impl Value {
         self.as_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub(crate) fn app_valuef(&self, val: ValueF) -> ValueF {
-        self.app_value(val.into_value_untyped())
-    }
-
     pub(crate) fn app_value(&self, th: Value) -> ValueF {
         apply_any(self.clone(), th)
     }
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 0d2655e..0c3058d 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -257,17 +257,17 @@ impl ValueF {
         }
     }
 
-    /// Apply to a value
+    /// Apply to a valuef
     pub(crate) fn app(self, val: ValueF) -> ValueF {
         self.app_valuef(val)
     }
 
-    /// Apply to a value
+    /// Apply to a valuef
     pub(crate) fn app_valuef(self, val: ValueF) -> ValueF {
         self.app_value(val.into_value_untyped())
     }
 
-    /// Apply to a thunk
+    /// Apply to a value
     pub fn app_value(self, th: Value) -> ValueF {
         Value::from_valuef_untyped(self).app_value(th)
     }
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 91d64c3..1f7e5f0 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -110,7 +110,7 @@ impl Typed {
         self.0.to_expr_alpha()
     }
     pub fn to_value(&self) -> Value {
-        self.0.to_value()
+        self.0.clone()
     }
     pub(crate) fn into_value(self) -> Value {
         self.0
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 76349e4..a379a4b 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -231,20 +231,28 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     unimplemented!()
                 }
             }
-            _ => Ok((
-                r,
-                f.app_valuef(ValueF::from_builtin(List).app_value(t.clone()))
-                    .app_value({
-                        // Move `t` under new `x` variable
-                        let t1 = t.under_binder(Label::from("x"));
-                        make_closure!(
-                            λ(x : #t) ->
-                            λ(xs : List #t1) ->
-                            [ var(x, 1) ] # var(xs, 0)
-                        )
-                    })
-                    .app_valuef(EmptyListLit(t.clone())),
-            )),
+            _ => {
+                let list_t = ValueF::from_builtin(List)
+                    .app_value(t.clone())
+                    .into_value_simple_type();
+                Ok((
+                    r,
+                    f.app_value(list_t.clone())
+                        .app_value({
+                            // Move `t` under new `x` variable
+                            let t1 = t.under_binder(Label::from("x"));
+                            make_closure!(
+                                λ(x : #t) ->
+                                λ(xs : List #t1) ->
+                                [ var(x, 1) ] # var(xs, 0)
+                            )
+                        })
+                        .app_value(
+                            EmptyListLit(t.clone())
+                                .into_value_with_type(list_t),
+                        ),
+                ))
+            }
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() {
             EmptyListLit(_) => Ok((r, nil.to_whnf())),
@@ -271,14 +279,20 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     unimplemented!()
                 }
             }
-            _ => Ok((
-                r,
-                f.app_valuef(
-                    ValueF::from_builtin(Optional).app_value(t.clone()),
-                )
-                .app_value(make_closure!(λ(x: #t) -> Some(var(x, 0))))
-                .app_valuef(EmptyOptionalLit(t.clone())),
-            )),
+            _ => {
+                let optional_t = ValueF::from_builtin(Optional)
+                    .app_value(t.clone())
+                    .into_value_simple_type();
+                Ok((
+                    r,
+                    f.app_value(optional_t.clone())
+                        .app_value(make_closure!(λ(x: #t) -> Some(var(x, 0))))
+                        .app_value(
+                            EmptyOptionalLit(t.clone())
+                                .into_value_with_type(optional_t),
+                        ),
+                ))
+            }
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
             EmptyOptionalLit(_) => Ok((r, nothing.to_whnf())),
@@ -295,12 +309,20 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     unimplemented!()
                 }
             }
-            _ => Ok((
-                r,
-                f.app_valuef(ValueF::from_builtin(Natural))
-                    .app_value(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
-                    .app_valuef(NaturalLit(0)),
-            )),
+            _ => {
+                let nat_type =
+                    ValueF::from_builtin(Natural).into_value_simple_type();
+                Ok((
+                    r,
+                    f.app_value(nat_type.clone())
+                        .app_value(
+                            make_closure!(λ(x : Natural) -> 1 + var(x, 0)),
+                        )
+                        .app_value(
+                            NaturalLit(0).into_value_with_type(nat_type),
+                        ),
+                ))
+            }
         },
         (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() {
             NaturalLit(0) => Ok((r, zero.to_whnf())),
@@ -309,8 +331,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     .app(NaturalLit(n - 1))
                     .app_value(t.clone())
                     .app_value(succ.clone())
-                    .app_value(zero.clone());
-                Ok((r, succ.app_valuef(fold)))
+                    .app_value(zero.clone())
+                    .into_value_with_type(t.clone());
+                Ok((r, succ.app_value(fold)))
             }
             _ => Err(()),
         },
@@ -571,8 +594,8 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
             let kvs = merge_maps(kvs1, kvs2, |v1, v2| {
                 Value::from_valuef_untyped(ValueF::PartialExpr(ExprF::BinOp(
                     RecursiveRecordTypeMerge,
-                    v1.to_value(),
-                    v2.to_value(),
+                    v1.clone(),
+                    v2.clone(),
                 )))
             });
             Ret::ValueF(RecordType(kvs))
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 8a3b43a..c47eb78 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -300,7 +300,7 @@ fn type_with(
             let tx = type_with(ctx, t.clone())?;
             let ctx2 = ctx.insert_type(x, tx.clone());
             let b = type_with(&ctx2, b.clone())?;
-            let v = ValueF::Lam(x.clone().into(), tx.clone(), b.to_value());
+            let v = ValueF::Lam(x.clone().into(), tx.clone(), b.clone());
             let tb = b.get_type()?.into_owned();
             let t = tck_pi_type(ctx, x.clone(), tx, tb)?;
             Value::from_valuef_and_type(v, t)
@@ -446,7 +446,7 @@ fn type_last_layer(
 
             RetTypeOnly(Value::from_valuef_and_type(
                 ValueF::from_builtin(dhall_syntax::Builtin::List)
-                    .app_value(t.to_value()),
+                    .app_value(t.into_owned()),
                 Value::from_const(Type),
             ))
         }
@@ -458,7 +458,7 @@ fn type_last_layer(
 
             RetTypeOnly(Value::from_valuef_and_type(
                 ValueF::from_builtin(dhall_syntax::Builtin::Optional)
-                    .app_value(t.to_value()),
+                    .app_value(t),
                 Value::from_const(Type),
             ))
         }
-- 
cgit v1.3.1


From 38a82c53ef45e802cf5816a8afcbf36a69c91174 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 14:12:27 +0200
Subject: Clarify conversion of Const/Builtin to Value

---
 dhall/src/core/value.rs      |  7 ++-----
 dhall/src/phase/typecheck.rs | 43 +++++++++++++++++++++++++++----------------
 2 files changed, 29 insertions(+), 21 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 0af7c8c..5367c86 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -9,7 +9,7 @@ use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::normalize::{apply_any, normalize_whnf, OutputSubExpr};
-use crate::phase::typecheck::type_of_const;
+use crate::phase::typecheck::const_to_value;
 use crate::phase::{NormalizedSubExpr, Typed};
 
 #[derive(Debug, Clone, Copy)]
@@ -110,10 +110,7 @@ impl Value {
         Value::from_valuef_and_type(v, Value::from_const(Const::Type))
     }
     pub(crate) fn from_const(c: Const) -> Self {
-        match type_of_const(c) {
-            Ok(t) => Value::from_valuef_and_type(ValueF::Const(c), t),
-            Err(_) => Value::from_valuef_untyped(ValueF::Const(c)),
-        }
+        const_to_value(c)
     }
     pub fn const_type() -> Self {
         Value::from_const(Const::Type)
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index c47eb78..1ea87d1 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -129,16 +129,24 @@ fn function_check(a: Const, b: Const) -> Const {
     }
 }
 
-pub(crate) fn type_of_const(c: Const) -> Result<Value, TypeError> {
+fn type_of_const(c: Const) -> Result<Value, TypeError> {
     match c {
-        Const::Type => Ok(Value::from_const(Const::Kind)),
-        Const::Kind => Ok(Value::from_const(Const::Sort)),
+        Const::Type => Ok(const_to_value(Const::Kind)),
+        Const::Kind => Ok(const_to_value(Const::Sort)),
         Const::Sort => {
             Err(TypeError::new(&TypecheckContext::new(), TypeMessage::Sort))
         }
     }
 }
 
+pub(crate) fn const_to_value(c: Const) -> Value {
+    let v = ValueF::Const(c);
+    match type_of_const(c) {
+        Ok(t) => Value::from_valuef_and_type(v, t),
+        Err(_) => Value::from_valuef_untyped(v),
+    }
+}
+
 // Ad-hoc macro to help construct the types of builtins
 macro_rules! make_type {
     (Type) => { ExprF::Const(Const::Type) };
@@ -280,9 +288,12 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
     }
 }
 
-// TODO: this can't fail in practise
-pub(crate) fn builtin_to_type(b: Builtin) -> Result<Value, TypeError> {
-    type_with(&TypecheckContext::new(), SubExpr::from_builtin(b))
+pub(crate) fn builtin_to_value(b: Builtin) -> Value {
+    let ctx = TypecheckContext::new();
+    Value::from_valuef_and_type(
+        ValueF::PartialExpr(ExprF::Builtin(b)),
+        type_with(&ctx, rc(type_of_builtin(b))).unwrap(),
+    )
 }
 
 /// Type-check an expression and return the expression alongside its type if type-checking
@@ -401,7 +412,7 @@ fn type_last_layer(
             RetTypeOnly(t.clone())
         }
         BoolIf(x, y, z) => {
-            if x.get_type()?.as_ref() != &builtin_to_type(Bool)? {
+            if x.get_type()?.as_ref() != &builtin_to_value(Bool) {
                 return mkerr(InvalidPredicate(x.clone()));
             }
 
@@ -523,14 +534,14 @@ fn type_last_layer(
                 // )),
             }
         }
-        Const(c) => RetWhole(Value::from_const(*c)),
-        Builtin(b) => RetTypeOnly(type_with(ctx, rc(type_of_builtin(*b)))?),
-        BoolLit(_) => RetTypeOnly(builtin_to_type(Bool)?),
-        NaturalLit(_) => RetTypeOnly(builtin_to_type(Natural)?),
-        IntegerLit(_) => RetTypeOnly(builtin_to_type(Integer)?),
-        DoubleLit(_) => RetTypeOnly(builtin_to_type(Double)?),
+        Const(c) => RetWhole(const_to_value(*c)),
+        Builtin(b) => RetWhole(builtin_to_value(*b)),
+        BoolLit(_) => RetTypeOnly(builtin_to_value(Bool)),
+        NaturalLit(_) => RetTypeOnly(builtin_to_value(Natural)),
+        IntegerLit(_) => RetTypeOnly(builtin_to_value(Integer)),
+        DoubleLit(_) => RetTypeOnly(builtin_to_value(Double)),
         TextLit(interpolated) => {
-            let text_type = builtin_to_type(Text)?;
+            let text_type = builtin_to_value(Text);
             for contents in interpolated.iter() {
                 use InterpolatedTextContents::Expr;
                 if let Expr(x) = contents {
@@ -665,7 +676,7 @@ fn type_last_layer(
             RetTypeOnly(Value::from_const(Type))
         }
         BinOp(o, l, r) => {
-            let t = builtin_to_type(match o {
+            let t = builtin_to_value(match o {
                 BoolAnd => Bool,
                 BoolOr => Bool,
                 BoolEQ => Bool,
@@ -679,7 +690,7 @@ fn type_last_layer(
                 RecursiveRecordTypeMerge => unreachable!(),
                 ImportAlt => unreachable!("There should remain no import alternatives in a resolved expression"),
                 Equivalence => unreachable!(),
-            })?;
+            });
 
             if l.get_type()?.as_ref() != &t {
                 return mkerr(BinOpTypeMismatch(*o, l.clone()));
-- 
cgit v1.3.1


From 04438824db21fb5d9d3a2abdb3fa167875bda892 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 16:39:27 +0200
Subject: Add Value::from_builtin

---
 dhall/src/core/value.rs      |  7 +++++--
 dhall/src/core/valuef.rs     | 10 ----------
 dhall/src/phase/normalize.rs | 44 +++++++++++++++++++-------------------------
 3 files changed, 24 insertions(+), 37 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 5367c86..f897f16 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -2,14 +2,14 @@ use std::borrow::Cow;
 use std::cell::{Ref, RefCell, RefMut};
 use std::rc::Rc;
 
-use dhall_syntax::Const;
+use dhall_syntax::{Builtin, Const};
 
 use crate::core::context::TypecheckContext;
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::normalize::{apply_any, normalize_whnf, OutputSubExpr};
-use crate::phase::typecheck::const_to_value;
+use crate::phase::typecheck::{builtin_to_value, const_to_value};
 use crate::phase::{NormalizedSubExpr, Typed};
 
 #[derive(Debug, Clone, Copy)]
@@ -115,6 +115,9 @@ impl Value {
     pub fn const_type() -> Self {
         Value::from_const(Const::Type)
     }
+    pub fn from_builtin(b: Builtin) -> Self {
+        builtin_to_value(b)
+    }
 
     pub(crate) fn as_const(&self) -> Option<Const> {
         match &*self.as_whnf() {
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 0c3058d..da03cbd 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -257,16 +257,6 @@ impl ValueF {
         }
     }
 
-    /// Apply to a valuef
-    pub(crate) fn app(self, val: ValueF) -> ValueF {
-        self.app_valuef(val)
-    }
-
-    /// Apply to a valuef
-    pub(crate) fn app_valuef(self, val: ValueF) -> ValueF {
-        self.app_value(val.into_value_untyped())
-    }
-
     /// Apply to a value
     pub fn app_value(self, th: Value) -> ValueF {
         Value::from_valuef_untyped(self).app_value(th)
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index a379a4b..f943171 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -31,11 +31,10 @@ macro_rules! make_closure {
         ).into_value_untyped()
     };
     (Natural) => {
-        ValueF::from_builtin(Builtin::Natural)
-            .into_value_simple_type()
+        Value::from_builtin(Builtin::Natural)
     };
     (List $($rest:tt)*) => {
-        ValueF::from_builtin(Builtin::List)
+        Value::from_builtin(Builtin::List)
             .app_value(make_closure!($($rest)*))
             .into_value_simple_type()
     };
@@ -192,10 +191,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
         (ListIndexed, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(t) => {
                 let mut kts = HashMap::new();
-                kts.insert(
-                    "index".into(),
-                    Value::from_valuef_untyped(ValueF::from_builtin(Natural)),
-                );
+                kts.insert("index".into(), Value::from_builtin(Natural));
                 kts.insert("value".into(), t.clone());
                 Ok((
                     r,
@@ -232,7 +228,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 }
             }
             _ => {
-                let list_t = ValueF::from_builtin(List)
+                let list_t = Value::from_builtin(List)
                     .app_value(t.clone())
                     .into_value_simple_type();
                 Ok((
@@ -280,7 +276,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 }
             }
             _ => {
-                let optional_t = ValueF::from_builtin(Optional)
+                let optional_t = Value::from_builtin(Optional)
                     .app_value(t.clone())
                     .into_value_simple_type();
                 Ok((
@@ -309,26 +305,24 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                     unimplemented!()
                 }
             }
-            _ => {
-                let nat_type =
-                    ValueF::from_builtin(Natural).into_value_simple_type();
-                Ok((
-                    r,
-                    f.app_value(nat_type.clone())
-                        .app_value(
-                            make_closure!(λ(x : Natural) -> 1 + var(x, 0)),
-                        )
-                        .app_value(
-                            NaturalLit(0).into_value_with_type(nat_type),
-                        ),
-                ))
-            }
+            _ => Ok((
+                r,
+                f.app_value(Value::from_builtin(Natural))
+                    .app_value(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
+                    .app_value(
+                        NaturalLit(0)
+                            .into_value_with_type(Value::from_builtin(Natural)),
+                    ),
+            )),
         },
         (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() {
             NaturalLit(0) => Ok((r, zero.to_whnf())),
             NaturalLit(n) => {
-                let fold = ValueF::from_builtin(NaturalFold)
-                    .app(NaturalLit(n - 1))
+                let fold = Value::from_builtin(NaturalFold)
+                    .app_value(
+                        NaturalLit(n - 1)
+                            .into_value_with_type(Value::from_builtin(Natural)),
+                    )
                     .app_value(t.clone())
                     .app_value(succ.clone())
                     .app_value(zero.clone())
-- 
cgit v1.3.1


From a506632b27b287d1bf898e2f77ae09a56902474c Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 17:08:01 +0200
Subject: Naming tweaks

---
 dhall/src/core/value.rs      |  6 ++---
 dhall/src/core/valuef.rs     | 11 +++++-----
 dhall/src/phase/normalize.rs | 52 ++++++++++++++++++++------------------------
 dhall/src/phase/typecheck.rs |  5 ++---
 serde_dhall/src/lib.rs       |  6 ++---
 5 files changed, 35 insertions(+), 45 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index f897f16..5055ac2 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -8,7 +8,7 @@ use crate::core::context::TypecheckContext;
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
-use crate::phase::normalize::{apply_any, normalize_whnf, OutputSubExpr};
+use crate::phase::normalize::{apply_any, normalize_whnf};
 use crate::phase::typecheck::{builtin_to_value, const_to_value};
 use crate::phase::{NormalizedSubExpr, Typed};
 
@@ -208,11 +208,11 @@ impl Value {
     pub(crate) fn normalize_to_expr_maybe_alpha(
         &self,
         alpha: bool,
-    ) -> OutputSubExpr {
+    ) -> NormalizedSubExpr {
         self.as_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub(crate) fn app_value(&self, th: Value) -> ValueF {
+    pub(crate) fn app(&self, th: Value) -> ValueF {
         apply_any(self.clone(), th)
     }
 
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index da03cbd..e9049c7 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -7,8 +7,7 @@ use dhall_syntax::{
 
 use crate::core::value::Value;
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
-use crate::phase::normalize::OutputSubExpr;
-use crate::phase::Normalized;
+use crate::phase::{Normalized, NormalizedSubExpr};
 
 /// A semantic value. Subexpressions are Values, which are partially evaluated expressions that are
 /// normalized on-demand.
@@ -59,7 +58,7 @@ impl ValueF {
     }
 
     /// Convert the value to a fully normalized syntactic expression
-    pub(crate) fn normalize_to_expr(&self) -> OutputSubExpr {
+    pub(crate) fn normalize_to_expr(&self) -> NormalizedSubExpr {
         self.normalize_to_expr_maybe_alpha(false)
     }
     /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
@@ -67,7 +66,7 @@ impl ValueF {
     pub(crate) fn normalize_to_expr_maybe_alpha(
         &self,
         alpha: bool,
-    ) -> OutputSubExpr {
+    ) -> NormalizedSubExpr {
         match self {
             ValueF::Lam(x, t, e) => rc(ExprF::Lam(
                 x.to_label_maybe_alpha(alpha),
@@ -258,8 +257,8 @@ impl ValueF {
     }
 
     /// Apply to a value
-    pub fn app_value(self, th: Value) -> ValueF {
-        Value::from_valuef_untyped(self).app_value(th)
+    pub fn app(self, th: Value) -> ValueF {
+        Value::from_valuef_untyped(self).app(th)
     }
 
     pub fn from_builtin(b: Builtin) -> ValueF {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index f943171..afc2e7f 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -8,9 +8,7 @@ use dhall_syntax::{
 use crate::core::value::Value;
 use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
-use crate::phase::{Normalized, NormalizedSubExpr};
-
-pub(crate) type OutputSubExpr = NormalizedSubExpr;
+use crate::phase::Normalized;
 
 // Ad-hoc macro to help construct closures
 macro_rules! make_closure {
@@ -35,7 +33,7 @@ macro_rules! make_closure {
     };
     (List $($rest:tt)*) => {
         Value::from_builtin(Builtin::List)
-            .app_value(make_closure!($($rest)*))
+            .app(make_closure!($($rest)*))
             .into_value_simple_type()
     };
     (Some($($rest:tt)*)) => {
@@ -229,12 +227,12 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
             _ => {
                 let list_t = Value::from_builtin(List)
-                    .app_value(t.clone())
+                    .app(t.clone())
                     .into_value_simple_type();
                 Ok((
                     r,
-                    f.app_value(list_t.clone())
-                        .app_value({
+                    f.app(list_t.clone())
+                        .app({
                             // Move `t` under new `x` variable
                             let t1 = t.under_binder(Label::from("x"));
                             make_closure!(
@@ -243,7 +241,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                                 [ var(x, 1) ] # var(xs, 0)
                             )
                         })
-                        .app_value(
+                        .app(
                             EmptyListLit(t.clone())
                                 .into_value_with_type(list_t),
                         ),
@@ -255,11 +253,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             NEListLit(xs) => {
                 let mut v = nil.clone();
                 for x in xs.iter().rev() {
-                    v = cons
-                        .clone()
-                        .app_value(x.clone())
-                        .app_value(v)
-                        .into_value_untyped();
+                    v = cons.clone().app(x.clone()).app(v).into_value_untyped();
                 }
                 Ok((r, v.to_whnf()))
             }
@@ -277,13 +271,13 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
             _ => {
                 let optional_t = Value::from_builtin(Optional)
-                    .app_value(t.clone())
+                    .app(t.clone())
                     .into_value_simple_type();
                 Ok((
                     r,
-                    f.app_value(optional_t.clone())
-                        .app_value(make_closure!(λ(x: #t) -> Some(var(x, 0))))
-                        .app_value(
+                    f.app(optional_t.clone())
+                        .app(make_closure!(λ(x: #t) -> Some(var(x, 0))))
+                        .app(
                             EmptyOptionalLit(t.clone())
                                 .into_value_with_type(optional_t),
                         ),
@@ -292,7 +286,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
             EmptyOptionalLit(_) => Ok((r, nothing.to_whnf())),
-            NEOptionalLit(x) => Ok((r, just.app_value(x.clone()))),
+            NEOptionalLit(x) => Ok((r, just.app(x.clone()))),
             _ => Err(()),
         },
         (NaturalBuild, [f, r..]) => match &*f.as_whnf() {
@@ -307,9 +301,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
             _ => Ok((
                 r,
-                f.app_value(Value::from_builtin(Natural))
-                    .app_value(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
-                    .app_value(
+                f.app(Value::from_builtin(Natural))
+                    .app(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
+                    .app(
                         NaturalLit(0)
                             .into_value_with_type(Value::from_builtin(Natural)),
                     ),
@@ -319,15 +313,15 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             NaturalLit(0) => Ok((r, zero.to_whnf())),
             NaturalLit(n) => {
                 let fold = Value::from_builtin(NaturalFold)
-                    .app_value(
+                    .app(
                         NaturalLit(n - 1)
                             .into_value_with_type(Value::from_builtin(Natural)),
                     )
-                    .app_value(t.clone())
-                    .app_value(succ.clone())
-                    .app_value(zero.clone())
+                    .app(t.clone())
+                    .app(succ.clone())
+                    .app(zero.clone())
                     .into_value_with_type(t.clone());
-                Ok((r, succ.app_value(fold)))
+                Ok((r, succ.app(fold)))
             }
             _ => Err(()),
         },
@@ -337,7 +331,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
         Ok((unconsumed_args, mut v)) => {
             let n_consumed_args = args.len() - unconsumed_args.len();
             for x in args.into_iter().skip(n_consumed_args) {
-                v = v.app_value(x);
+                v = v.app(x);
             }
             v
         }
@@ -621,7 +615,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         ExprF::Lam(x, t, e) => Ret::ValueF(Lam(x.into(), t, e)),
         ExprF::Pi(x, t, e) => Ret::ValueF(Pi(x.into(), t, e)),
         ExprF::Let(x, _, v, b) => Ret::Value(b.subst_shift(&x.into(), &v)),
-        ExprF::App(v, a) => Ret::ValueF(v.app_value(a)),
+        ExprF::App(v, a) => Ret::ValueF(v.app(a)),
         ExprF::Builtin(b) => Ret::ValueF(ValueF::from_builtin(b)),
         ExprF::Const(c) => Ret::ValueF(ValueF::Const(c)),
         ExprF::BoolLit(b) => Ret::ValueF(BoolLit(b)),
@@ -743,7 +737,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
                     }
                 },
                 (RecordLit(kvs), UnionLit(l, v, _)) => match kvs.get(l) {
-                    Some(h) => Ret::ValueF(h.app_value(v.clone())),
+                    Some(h) => Ret::ValueF(h.app(v.clone())),
                     None => {
                         drop(handlers_borrow);
                         drop(variant_borrow);
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 1ea87d1..440d694 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -457,7 +457,7 @@ fn type_last_layer(
 
             RetTypeOnly(Value::from_valuef_and_type(
                 ValueF::from_builtin(dhall_syntax::Builtin::List)
-                    .app_value(t.into_owned()),
+                    .app(t.into_owned()),
                 Value::from_const(Type),
             ))
         }
@@ -468,8 +468,7 @@ fn type_last_layer(
             }
 
             RetTypeOnly(Value::from_valuef_and_type(
-                ValueF::from_builtin(dhall_syntax::Builtin::Optional)
-                    .app_value(t),
+                ValueF::from_builtin(dhall_syntax::Builtin::Optional).app(t),
                 Value::from_const(Type),
             ))
         }
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index cef11dd..4171fab 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -169,14 +169,12 @@ pub mod value {
         }
         pub(crate) fn make_optional_type(t: Value) -> Self {
             Self::make_simple_type(
-                DhallValueF::from_builtin(Builtin::Optional)
-                    .app_value(t.to_value()),
+                DhallValueF::from_builtin(Builtin::Optional).app(t.to_value()),
             )
         }
         pub(crate) fn make_list_type(t: Value) -> Self {
             Self::make_simple_type(
-                DhallValueF::from_builtin(Builtin::List)
-                    .app_value(t.to_value()),
+                DhallValueF::from_builtin(Builtin::List).app(t.to_value()),
             )
         }
         // Made public for the StaticType derive macro
-- 
cgit v1.3.1


From 4f1f37cfc115510500e83d2dfbfa8ed7ddeae74a Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 18:03:59 +0200
Subject: Introduce a new enum to store either a Value or a ValueF

---
 dhall/src/core/value.rs      |  54 ++++++++++++++++-
 dhall/src/core/valuef.rs     |   9 ++-
 dhall/src/phase/normalize.rs | 141 +++++++++++++++++++++++++------------------
 dhall/src/phase/typecheck.rs |  17 +++---
 serde_dhall/src/lib.rs       |   8 ++-
 5 files changed, 153 insertions(+), 76 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 5055ac2..25fcaae 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -44,6 +44,14 @@ struct ValueInternal {
 #[derive(Clone)]
 pub struct Value(Rc<RefCell<ValueInternal>>);
 
+/// When a function needs to return either a freshly created ValueF or an existing Value, but
+/// doesn't want to convert both to the same thing, either to avoid unnecessary allocations or to
+/// avoid loss of typ information.
+pub enum VoVF {
+    Value(Value),
+    ValueF(ValueF),
+}
+
 impl ValueInternal {
     fn into_value(self) -> Value {
         Value(Rc::new(RefCell::new(self)))
@@ -56,7 +64,8 @@ impl ValueInternal {
         take_mut::take(self, |vint| match &vint.form {
             Unevaled => ValueInternal {
                 form: WHNF,
-                value: normalize_whnf(vint.value),
+                // TODO: thunk chaining
+                value: normalize_whnf(vint.value).into_whnf(),
                 ty: vint.ty,
             },
             // Already in WHNF
@@ -166,6 +175,9 @@ impl Value {
     pub(crate) fn into_typed(self) -> Typed {
         Typed::from_value(self)
     }
+    pub(crate) fn into_vovf(self) -> VoVF {
+        VoVF::Value(self)
+    }
 
     /// Mutates the contents. If no one else shares this, this avoids a RefCell lock.
     fn mutate_internal(&mut self, f: impl FnOnce(&mut ValueInternal)) {
@@ -212,8 +224,8 @@ impl Value {
         self.as_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub(crate) fn app(&self, th: Value) -> ValueF {
-        apply_any(self.clone(), th)
+    pub(crate) fn app(&self, v: Value) -> VoVF {
+        apply_any(self.clone(), v)
     }
 
     pub(crate) fn get_type(&self) -> Result<Cow<'_, Value>, TypeError> {
@@ -221,6 +233,42 @@ impl Value {
     }
 }
 
+impl VoVF {
+    pub fn into_whnf(self) -> ValueF {
+        match self {
+            VoVF::Value(v) => v.to_whnf(),
+            VoVF::ValueF(v) => v,
+        }
+    }
+    pub(crate) fn into_value_untyped(self) -> Value {
+        match self {
+            VoVF::Value(v) => v,
+            VoVF::ValueF(v) => v.into_value_untyped(),
+        }
+    }
+    pub(crate) fn into_value_with_type(self, t: Value) -> Value {
+        match self {
+            // TODO: check type with debug_assert ?
+            VoVF::Value(v) => v,
+            VoVF::ValueF(v) => v.into_value_with_type(t),
+        }
+    }
+    pub(crate) fn into_value_simple_type(self) -> Value {
+        match self {
+            // TODO: check type with debug_assert ?
+            VoVF::Value(v) => v,
+            VoVF::ValueF(v) => v.into_value_simple_type(),
+        }
+    }
+
+    pub(crate) fn app(self, x: Value) -> Self {
+        match self {
+            VoVF::Value(v) => v.app(x),
+            VoVF::ValueF(v) => v.into_value_untyped().app(x),
+        }
+    }
+}
+
 impl Shift for Value {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(Value(self.0.shift(delta, var)?))
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index e9049c7..80978a7 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble, Natural,
 };
 
-use crate::core::value::Value;
+use crate::core::value::{Value, VoVF};
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr};
 
@@ -56,6 +56,9 @@ impl ValueF {
     pub(crate) fn into_value_simple_type(self) -> Value {
         Value::from_valuef_simple_type(self)
     }
+    pub(crate) fn into_vovf(self) -> VoVF {
+        VoVF::ValueF(self)
+    }
 
     /// Convert the value to a fully normalized syntactic expression
     pub(crate) fn normalize_to_expr(&self) -> NormalizedSubExpr {
@@ -257,8 +260,8 @@ impl ValueF {
     }
 
     /// Apply to a value
-    pub fn app(self, th: Value) -> ValueF {
-        Value::from_valuef_untyped(self).app(th)
+    pub fn app(self, v: Value) -> VoVF {
+        self.into_vovf().app(v)
     }
 
     pub fn from_builtin(b: Builtin) -> ValueF {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index afc2e7f..e044018 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble,
 };
 
-use crate::core::value::Value;
+use crate::core::value::{Value, VoVF};
 use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::phase::Normalized;
@@ -63,44 +63,48 @@ macro_rules! make_closure {
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
+pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
     use dhall_syntax::Builtin::*;
     use ValueF::*;
 
     // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
     let ret = match (b, args.as_slice()) {
-        (OptionalNone, [t, r..]) => Ok((r, EmptyOptionalLit(t.clone()))),
+        (OptionalNone, [t, r..]) => {
+            Ok((r, EmptyOptionalLit(t.clone()).into_vovf()))
+        }
         (NaturalIsZero, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
+            NaturalLit(n) => Ok((r, BoolLit(*n == 0).into_vovf())),
             _ => Err(()),
         },
         (NaturalEven, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0))),
+            NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0).into_vovf())),
             _ => Err(()),
         },
         (NaturalOdd, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0))),
+            NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0).into_vovf())),
             _ => Err(()),
         },
         (NaturalToInteger, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, IntegerLit(*n as isize))),
+            NaturalLit(n) => Ok((r, IntegerLit(*n as isize).into_vovf())),
             _ => Err(()),
         },
         (NaturalShow, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((
                 r,
-                TextLit(vec![InterpolatedTextContents::Text(n.to_string())]),
+                TextLit(vec![InterpolatedTextContents::Text(n.to_string())])
+                    .into_vovf(),
             )),
             _ => Err(()),
         },
         (NaturalSubtract, [a, b, r..]) => {
             match (&*a.as_whnf(), &*b.as_whnf()) {
-                (NaturalLit(a), NaturalLit(b)) => {
-                    Ok((r, NaturalLit(if b > a { b - a } else { 0 })))
-                }
-                (NaturalLit(0), b) => Ok((r, b.clone())),
-                (_, NaturalLit(0)) => Ok((r, NaturalLit(0))),
-                _ if a == b => Ok((r, NaturalLit(0))),
+                (NaturalLit(a), NaturalLit(b)) => Ok((
+                    r,
+                    NaturalLit(if b > a { b - a } else { 0 }).into_vovf(),
+                )),
+                (NaturalLit(0), _) => Ok((r, b.clone().into_vovf())),
+                (_, NaturalLit(0)) => Ok((r, NaturalLit(0).into_vovf())),
+                _ if a == b => Ok((r, NaturalLit(0).into_vovf())),
                 _ => Err(()),
             }
         }
@@ -111,18 +115,25 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 } else {
                     format!("+{}", n)
                 };
-                Ok((r, TextLit(vec![InterpolatedTextContents::Text(s)])))
+                Ok((
+                    r,
+                    TextLit(vec![InterpolatedTextContents::Text(s)])
+                        .into_vovf(),
+                ))
             }
             _ => Err(()),
         },
         (IntegerToDouble, [n, r..]) => match &*n.as_whnf() {
-            IntegerLit(n) => Ok((r, DoubleLit(NaiveDouble::from(*n as f64)))),
+            IntegerLit(n) => {
+                Ok((r, DoubleLit(NaiveDouble::from(*n as f64)).into_vovf()))
+            }
             _ => Err(()),
         },
         (DoubleShow, [n, r..]) => match &*n.as_whnf() {
             DoubleLit(n) => Ok((
                 r,
-                TextLit(vec![InterpolatedTextContents::Text(n.to_string())]),
+                TextLit(vec![InterpolatedTextContents::Text(n.to_string())])
+                    .into_vovf(),
             )),
             _ => Err(()),
         },
@@ -137,7 +148,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                         let s = txt.to_string();
                         Ok((
                             r,
-                            TextLit(vec![InterpolatedTextContents::Text(s)]),
+                            TextLit(vec![InterpolatedTextContents::Text(s)])
+                                .into_vovf(),
                         ))
                     }
                     // If there are no interpolations (invariants ensure that when there are no
@@ -152,7 +164,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                         let s = txt.to_string();
                         Ok((
                             r,
-                            TextLit(vec![InterpolatedTextContents::Text(s)]),
+                            TextLit(vec![InterpolatedTextContents::Text(s)])
+                                .into_vovf(),
                         ))
                     }
                     _ => Err(()),
@@ -161,29 +174,33 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             _ => Err(()),
         },
         (ListLength, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(_) => Ok((r, NaturalLit(0))),
-            NEListLit(xs) => Ok((r, NaturalLit(xs.len()))),
+            EmptyListLit(_) => Ok((r, NaturalLit(0).into_vovf())),
+            NEListLit(xs) => Ok((r, NaturalLit(xs.len()).into_vovf())),
             _ => Err(()),
         },
         (ListHead, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))),
-            NEListLit(xs) => {
-                Ok((r, NEOptionalLit(xs.iter().next().unwrap().clone())))
-            }
+            EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()).into_vovf())),
+            NEListLit(xs) => Ok((
+                r,
+                NEOptionalLit(xs.iter().next().unwrap().clone()).into_vovf(),
+            )),
             _ => Err(()),
         },
         (ListLast, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))),
-            NEListLit(xs) => {
-                Ok((r, NEOptionalLit(xs.iter().rev().next().unwrap().clone())))
-            }
+            EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()).into_vovf())),
+            NEListLit(xs) => Ok((
+                r,
+                NEOptionalLit(xs.iter().rev().next().unwrap().clone())
+                    .into_vovf(),
+            )),
             _ => Err(()),
         },
         (ListReverse, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => Ok((r, EmptyListLit(n.clone()))),
-            NEListLit(xs) => {
-                Ok((r, NEListLit(xs.iter().rev().cloned().collect())))
-            }
+            EmptyListLit(n) => Ok((r, EmptyListLit(n.clone()).into_vovf())),
+            NEListLit(xs) => Ok((
+                r,
+                NEListLit(xs.iter().rev().cloned().collect()).into_vovf(),
+            )),
             _ => Err(()),
         },
         (ListIndexed, [_, l, r..]) => match &*l.as_whnf() {
@@ -193,7 +210,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                 kts.insert("value".into(), t.clone());
                 Ok((
                     r,
-                    EmptyListLit(Value::from_valuef_untyped(RecordType(kts))),
+                    EmptyListLit(Value::from_valuef_untyped(RecordType(kts)))
+                        .into_vovf(),
                 ))
             }
             NEListLit(xs) => {
@@ -211,7 +229,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
                         Value::from_valuef_untyped(RecordLit(kvs))
                     })
                     .collect();
-                Ok((r, NEListLit(xs)))
+                Ok((r, NEListLit(xs).into_vovf()))
             }
             _ => Err(()),
         },
@@ -219,7 +237,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             // fold/build fusion
             ValueF::AppliedBuiltin(ListFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].to_whnf()))
+                    Ok((r, args[1].clone().into_vovf()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -249,13 +267,13 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() {
-            EmptyListLit(_) => Ok((r, nil.to_whnf())),
+            EmptyListLit(_) => Ok((r, nil.clone().into_vovf())),
             NEListLit(xs) => {
-                let mut v = nil.clone();
-                for x in xs.iter().rev() {
-                    v = cons.clone().app(x.clone()).app(v).into_value_untyped();
+                let mut v = nil.clone().into_vovf();
+                for x in xs.iter().cloned().rev() {
+                    v = cons.app(x).app(v.into_value_untyped());
                 }
-                Ok((r, v.to_whnf()))
+                Ok((r, v))
             }
             _ => Err(()),
         },
@@ -263,7 +281,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             // fold/build fusion
             ValueF::AppliedBuiltin(OptionalFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].to_whnf()))
+                    Ok((r, args[1].clone().into_vovf()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -285,7 +303,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
-            EmptyOptionalLit(_) => Ok((r, nothing.to_whnf())),
+            EmptyOptionalLit(_) => Ok((r, nothing.clone().into_vovf())),
             NEOptionalLit(x) => Ok((r, just.app(x.clone()))),
             _ => Err(()),
         },
@@ -293,7 +311,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             // fold/build fusion
             ValueF::AppliedBuiltin(NaturalFold, args) => {
                 if !args.is_empty() {
-                    Ok((r, args[0].to_whnf()))
+                    Ok((r, args[0].clone().into_vovf()))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -310,7 +328,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             )),
         },
         (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() {
-            NaturalLit(0) => Ok((r, zero.to_whnf())),
+            NaturalLit(0) => Ok((r, zero.clone().into_vovf())),
             NaturalLit(n) => {
                 let fold = Value::from_builtin(NaturalFold)
                     .app(
@@ -335,23 +353,24 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> ValueF {
             }
             v
         }
-        Err(()) => AppliedBuiltin(b, args),
+        Err(()) => AppliedBuiltin(b, args).into_vovf(),
     }
 }
 
-pub(crate) fn apply_any(f: Value, a: Value) -> ValueF {
-    let fallback = |f: Value, a: Value| ValueF::PartialExpr(ExprF::App(f, a));
+pub(crate) fn apply_any(f: Value, a: Value) -> VoVF {
+    let fallback =
+        |f: Value, a: Value| ValueF::PartialExpr(ExprF::App(f, a)).into_vovf();
 
     let f_borrow = f.as_whnf();
     match &*f_borrow {
-        ValueF::Lam(x, _, e) => e.subst_shift(&x.into(), &a).to_whnf(),
+        ValueF::Lam(x, _, e) => e.subst_shift(&x.into(), &a).into_vovf(),
         ValueF::AppliedBuiltin(b, args) => {
             use std::iter::once;
             let args = args.iter().cloned().chain(once(a.clone())).collect();
             apply_builtin(*b, args)
         }
         ValueF::UnionConstructor(l, kts) => {
-            ValueF::UnionLit(l.clone(), a, kts.clone())
+            ValueF::UnionLit(l.clone(), a, kts.clone()).into_vovf()
         }
         _ => {
             drop(f_borrow);
@@ -465,6 +484,7 @@ where
 enum Ret<'a> {
     ValueF(ValueF),
     Value(Value),
+    VoVF(VoVF),
     ValueRef(&'a Value),
     Expr(ExprF<Value, Normalized>),
 }
@@ -597,7 +617,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
     })
 }
 
-pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
+pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
     use ValueF::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, Lam,
         NEListLit, NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType,
@@ -615,7 +635,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
         ExprF::Lam(x, t, e) => Ret::ValueF(Lam(x.into(), t, e)),
         ExprF::Pi(x, t, e) => Ret::ValueF(Pi(x.into(), t, e)),
         ExprF::Let(x, _, v, b) => Ret::Value(b.subst_shift(&x.into(), &v)),
-        ExprF::App(v, a) => Ret::ValueF(v.app(a)),
+        ExprF::App(v, a) => Ret::VoVF(v.app(a)),
         ExprF::Builtin(b) => Ret::ValueF(ValueF::from_builtin(b)),
         ExprF::Const(c) => Ret::ValueF(ValueF::Const(c)),
         ExprF::BoolLit(b) => Ret::ValueF(BoolLit(b)),
@@ -737,7 +757,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
                     }
                 },
                 (RecordLit(kvs), UnionLit(l, v, _)) => match kvs.get(l) {
-                    Some(h) => Ret::ValueF(h.app(v.clone())),
+                    Some(h) => Ret::VoVF(h.app(v.clone())),
                     None => {
                         drop(handlers_borrow);
                         drop(variant_borrow);
@@ -754,22 +774,23 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> ValueF {
     };
 
     match ret {
-        Ret::ValueF(v) => v,
-        Ret::Value(th) => th.as_whnf().clone(),
-        Ret::ValueRef(th) => th.as_whnf().clone(),
-        Ret::Expr(expr) => ValueF::PartialExpr(expr),
+        Ret::ValueF(v) => v.into_vovf(),
+        Ret::Value(v) => v.into_vovf(),
+        Ret::VoVF(v) => v,
+        Ret::ValueRef(v) => v.clone().into_vovf(),
+        Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf(),
     }
 }
 
 /// Normalize a ValueF into WHNF
-pub(crate) fn normalize_whnf(v: ValueF) -> ValueF {
+pub(crate) fn normalize_whnf(v: ValueF) -> VoVF {
     match v {
         ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args),
         ValueF::PartialExpr(e) => normalize_one_layer(e),
         ValueF::TextLit(elts) => {
-            ValueF::TextLit(squash_textlit(elts.into_iter()))
+            ValueF::TextLit(squash_textlit(elts.into_iter())).into_vovf()
         }
         // All other cases are already in WHNF
-        v => v,
+        v => v.into_vovf(),
     }
 }
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 440d694..996c26c 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -455,11 +455,11 @@ fn type_last_layer(
                 return mkerr(InvalidListType(t.into_owned()));
             }
 
-            RetTypeOnly(Value::from_valuef_and_type(
+            RetTypeOnly(
                 ValueF::from_builtin(dhall_syntax::Builtin::List)
-                    .app(t.into_owned()),
-                Value::from_const(Type),
-            ))
+                    .app(t.into_owned())
+                    .into_value_simple_type(),
+            )
         }
         SomeLit(x) => {
             let t = x.get_type()?.into_owned();
@@ -467,10 +467,11 @@ fn type_last_layer(
                 return mkerr(InvalidOptionalType(t));
             }
 
-            RetTypeOnly(Value::from_valuef_and_type(
-                ValueF::from_builtin(dhall_syntax::Builtin::Optional).app(t),
-                Value::from_const(Type),
-            ))
+            RetTypeOnly(
+                Value::from_builtin(dhall_syntax::Builtin::Optional)
+                    .app(t)
+                    .into_value_simple_type(),
+            )
         }
         RecordType(kts) => RetWhole(tck_record_type(
             ctx,
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 4171fab..e2449de 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -169,12 +169,16 @@ pub mod value {
         }
         pub(crate) fn make_optional_type(t: Value) -> Self {
             Self::make_simple_type(
-                DhallValueF::from_builtin(Builtin::Optional).app(t.to_value()),
+                DhallValueF::from_builtin(Builtin::Optional)
+                    .app(t.to_value())
+                    .into_whnf(),
             )
         }
         pub(crate) fn make_list_type(t: Value) -> Self {
             Self::make_simple_type(
-                DhallValueF::from_builtin(Builtin::List).app(t.to_value()),
+                DhallValueF::from_builtin(Builtin::List)
+                    .app(t.to_value())
+                    .into_whnf(),
             )
         }
         // Made public for the StaticType derive macro
-- 
cgit v1.3.1


From c157df5e66fb80ff6184cb3934e5b0883f0fdbf0 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 18:11:05 +0200
Subject: No need for Cow in return type of get_type

---
 dhall/src/core/value.rs      |  5 ++---
 dhall/src/phase/mod.rs       |  5 ++---
 dhall/src/phase/typecheck.rs | 39 +++++++++++++++++++--------------------
 dhall/src/tests.rs           |  2 +-
 4 files changed, 24 insertions(+), 27 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 25fcaae..64a4842 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -1,4 +1,3 @@
-use std::borrow::Cow;
 use std::cell::{Ref, RefCell, RefMut};
 use std::rc::Rc;
 
@@ -228,8 +227,8 @@ impl Value {
         apply_any(self.clone(), v)
     }
 
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, Value>, TypeError> {
-        Ok(Cow::Owned(self.as_internal().get_type()?.clone()))
+    pub(crate) fn get_type(&self) -> Result<Value, TypeError> {
+        Ok(self.as_internal().get_type()?.clone())
     }
 }
 
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 1f7e5f0..1f80791 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -1,4 +1,3 @@
-use std::borrow::Cow;
 use std::fmt::Display;
 use std::path::Path;
 
@@ -121,8 +120,8 @@ impl Typed {
     }
 
     #[allow(dead_code)]
-    pub(crate) fn get_type(&self) -> Result<Cow<'_, Typed>, TypeError> {
-        Ok(Cow::Owned(self.0.get_type()?.into_owned().into_typed()))
+    pub(crate) fn get_type(&self) -> Result<Typed, TypeError> {
+        Ok(self.0.get_type()?.into_typed())
     }
 }
 
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 996c26c..4abc314 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -31,7 +31,7 @@ fn tck_pi_type(
         _ => {
             return Err(TypeError::new(
                 &ctx2,
-                InvalidOutputType(te.get_type()?.into_owned()),
+                InvalidOutputType(te.get_type()?),
             ))
         }
     };
@@ -312,7 +312,7 @@ fn type_with(
             let ctx2 = ctx.insert_type(x, tx.clone());
             let b = type_with(&ctx2, b.clone())?;
             let v = ValueF::Lam(x.clone().into(), tx.clone(), b.clone());
-            let tb = b.get_type()?.into_owned();
+            let tb = b.get_type()?;
             let t = tck_pi_type(ctx, x.clone(), tx, tb)?;
             Value::from_valuef_and_type(v, t)
         }
@@ -389,17 +389,17 @@ fn type_last_layer(
                 ValueF::Pi(x, tx, tb) => (x, tx, tb),
                 _ => return mkerr(NotAFunction(f.clone())),
             };
-            if a.get_type()?.as_ref() != tx {
+            if &a.get_type()? != tx {
                 return mkerr(TypeMismatch(f.clone(), tx.clone(), a.clone()));
             }
 
             RetTypeOnly(tb.subst_shift(&x.into(), a))
         }
         Annot(x, t) => {
-            if t != x.get_type()?.as_ref() {
+            if &x.get_type()? != t {
                 return mkerr(AnnotMismatch(x.clone(), t.clone()));
             }
-            RetTypeOnly(x.get_type()?.into_owned())
+            RetTypeOnly(x.get_type()?)
         }
         Assert(t) => {
             match &*t.as_whnf() {
@@ -412,7 +412,7 @@ fn type_last_layer(
             RetTypeOnly(t.clone())
         }
         BoolIf(x, y, z) => {
-            if x.get_type()?.as_ref() != &builtin_to_value(Bool) {
+            if &*x.get_type()?.as_whnf() != &ValueF::from_builtin(Bool) {
                 return mkerr(InvalidPredicate(x.clone()));
             }
 
@@ -428,7 +428,7 @@ fn type_last_layer(
                 return mkerr(IfBranchMismatch(y.clone(), z.clone()));
             }
 
-            RetTypeOnly(y.get_type()?.into_owned())
+            RetTypeOnly(y.get_type()?)
         }
         EmptyListLit(t) => {
             match &*t.as_whnf() {
@@ -445,24 +445,24 @@ fn type_last_layer(
                 if x.get_type()? != y.get_type()? {
                     return mkerr(InvalidListElement(
                         i,
-                        x.get_type()?.into_owned(),
+                        x.get_type()?,
                         y.clone(),
                     ));
                 }
             }
             let t = x.get_type()?;
             if t.get_type()?.as_const() != Some(Type) {
-                return mkerr(InvalidListType(t.into_owned()));
+                return mkerr(InvalidListType(t));
             }
 
             RetTypeOnly(
                 ValueF::from_builtin(dhall_syntax::Builtin::List)
-                    .app(t.into_owned())
+                    .app(t)
                     .into_value_simple_type(),
             )
         }
         SomeLit(x) => {
-            let t = x.get_type()?.into_owned();
+            let t = x.get_type()?;
             if t.get_type()?.as_const() != Some(Type) {
                 return mkerr(InvalidOptionalType(t));
             }
@@ -483,8 +483,7 @@ fn type_last_layer(
         )?),
         RecordLit(kvs) => RetTypeOnly(tck_record_type(
             ctx,
-            kvs.iter()
-                .map(|(x, v)| Ok((x.clone(), v.get_type()?.into_owned()))),
+            kvs.iter().map(|(x, v)| Ok((x.clone(), v.get_type()?))),
         )?),
         Field(r, x) => {
             match &*r.get_type()?.as_whnf() {
@@ -545,7 +544,7 @@ fn type_last_layer(
             for contents in interpolated.iter() {
                 use InterpolatedTextContents::Expr;
                 if let Expr(x) = contents {
-                    if x.get_type()?.as_ref() != &text_type {
+                    if x.get_type()? != text_type {
                         return mkerr(InvalidTextInterpolation(x.clone()));
                     }
                 }
@@ -586,8 +585,8 @@ fn type_last_layer(
             ctx,
             ExprF::BinOp(
                 RecursiveRecordTypeMerge,
-                l.get_type()?.into_owned(),
-                r.get_type()?.into_owned(),
+                l.get_type()?,
+                r.get_type()?,
             ),
         )?),
         BinOp(RecursiveRecordTypeMerge, l, r) => {
@@ -659,7 +658,7 @@ fn type_last_layer(
                 return mkerr(BinOpTypeMismatch(*o, r.clone()));
             }
 
-            RetTypeOnly(l.get_type()?.into_owned())
+            RetTypeOnly(l.get_type()?)
         }
         BinOp(Equivalence, l, r) => {
             if l.get_type()?.get_type()?.as_const() != Some(Type) {
@@ -692,11 +691,11 @@ fn type_last_layer(
                 Equivalence => unreachable!(),
             });
 
-            if l.get_type()?.as_ref() != &t {
+            if l.get_type()? != t {
                 return mkerr(BinOpTypeMismatch(*o, l.clone()));
             }
 
-            if r.get_type()?.as_ref() != &t {
+            if r.get_type()? != t {
                 return mkerr(BinOpTypeMismatch(*o, r.clone()));
             }
 
@@ -800,7 +799,7 @@ fn type_last_layer(
 
             RetTypeOnly(Value::from_valuef_and_type(
                 ValueF::RecordType(new_kts),
-                record_type.get_type()?.into_owned(),
+                record_type.get_type()?,
             ))
         }
     };
diff --git a/dhall/src/tests.rs b/dhall/src/tests.rs
index be4805d..8f16a12 100644
--- a/dhall/src/tests.rs
+++ b/dhall/src/tests.rs
@@ -185,7 +185,7 @@ pub fn run_test(
                 }
                 TypeInference => {
                     let expr = expr.typecheck()?;
-                    let ty = expr.get_type()?.into_owned().normalize();
+                    let ty = expr.get_type()?.normalize();
                     assert_eq_display!(ty, expected);
                 }
                 Normalization => {
-- 
cgit v1.3.1


From f70e45daef2570259eccd227a0126493c015d7b0 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 21:50:47 +0200
Subject: Track evaluation status alongside ValueF in VoVF

---
 dhall/src/core/value.rs      | 44 +++++++++++----------------
 dhall/src/core/valuef.rs     | 32 ++++++++++++++------
 dhall/src/phase/normalize.rs | 72 ++++++++++++++++++++++++--------------------
 3 files changed, 80 insertions(+), 68 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 64a4842..b44dad6 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -12,7 +12,7 @@ use crate::phase::typecheck::{builtin_to_value, const_to_value};
 use crate::phase::{NormalizedSubExpr, Typed};
 
 #[derive(Debug, Clone, Copy)]
-enum Form {
+pub enum Form {
     /// No constraints; expression may not be normalized at all.
     Unevaled,
     /// Weak Head Normal Form, i.e. normalized up to the first constructor, but subexpressions may
@@ -46,9 +46,10 @@ pub struct Value(Rc<RefCell<ValueInternal>>);
 /// When a function needs to return either a freshly created ValueF or an existing Value, but
 /// doesn't want to convert both to the same thing, either to avoid unnecessary allocations or to
 /// avoid loss of typ information.
+#[derive(Debug, Clone)]
 pub enum VoVF {
     Value(Value),
-    ValueF(ValueF),
+    ValueF { val: ValueF, form: Form },
 }
 
 impl ValueInternal {
@@ -98,24 +99,14 @@ impl ValueInternal {
 }
 
 impl Value {
+    pub(crate) fn new(value: ValueF, form: Form, ty: Option<Value>) -> Value {
+        ValueInternal { form, value, ty }.into_value()
+    }
     pub(crate) fn from_valuef_untyped(v: ValueF) -> Value {
-        ValueInternal {
-            form: Unevaled,
-            value: v,
-            ty: None,
-        }
-        .into_value()
+        Value::new(v, Unevaled, None)
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Value) -> Value {
-        ValueInternal {
-            form: Unevaled,
-            value: v,
-            ty: Some(t),
-        }
-        .into_value()
-    }
-    pub(crate) fn from_valuef_simple_type(v: ValueF) -> Value {
-        Value::from_valuef_and_type(v, Value::from_const(Const::Type))
+        Value::new(v, Unevaled, Some(t))
     }
     pub(crate) fn from_const(c: Const) -> Self {
         const_to_value(c)
@@ -236,34 +227,35 @@ impl VoVF {
     pub fn into_whnf(self) -> ValueF {
         match self {
             VoVF::Value(v) => v.to_whnf(),
-            VoVF::ValueF(v) => v,
+            VoVF::ValueF {
+                val,
+                form: Unevaled,
+            } => normalize_whnf(val).into_whnf(),
+            // Already at lest in WHNF
+            VoVF::ValueF { val, .. } => val,
         }
     }
     pub(crate) fn into_value_untyped(self) -> Value {
         match self {
             VoVF::Value(v) => v,
-            VoVF::ValueF(v) => v.into_value_untyped(),
+            VoVF::ValueF { val, form } => Value::new(val, form, None),
         }
     }
     pub(crate) fn into_value_with_type(self, t: Value) -> Value {
         match self {
             // TODO: check type with debug_assert ?
             VoVF::Value(v) => v,
-            VoVF::ValueF(v) => v.into_value_with_type(t),
+            VoVF::ValueF { val, form } => Value::new(val, form, Some(t)),
         }
     }
     pub(crate) fn into_value_simple_type(self) -> Value {
-        match self {
-            // TODO: check type with debug_assert ?
-            VoVF::Value(v) => v,
-            VoVF::ValueF(v) => v.into_value_simple_type(),
-        }
+        self.into_value_with_type(Value::from_const(Const::Type))
     }
 
     pub(crate) fn app(self, x: Value) -> Self {
         match self {
             VoVF::Value(v) => v.app(x),
-            VoVF::ValueF(v) => v.into_value_untyped().app(x),
+            VoVF::ValueF { val, .. } => val.into_value_untyped().app(x),
         }
     }
 }
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 80978a7..db8a284 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble, Natural,
 };
 
-use crate::core::value::{Value, VoVF};
+use crate::core::value::{Form, Value, VoVF};
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr};
 
@@ -19,7 +19,7 @@ pub enum ValueF {
     /// Closures
     Lam(AlphaLabel, Value, Value),
     Pi(AlphaLabel, Value, Value),
-    // Invariant: the evaluation must not be able to progress further.
+    // Invariant: in whnf, the evaluation must not be able to progress further.
     AppliedBuiltin(Builtin, Vec<Value>),
 
     Var(AlphaVar),
@@ -33,16 +33,16 @@ pub enum ValueF {
     // EmptyListLit(t) means `[] : List t`, not `[] : t`
     EmptyListLit(Value),
     NEListLit(Vec<Value>),
-    RecordLit(HashMap<Label, Value>),
     RecordType(HashMap<Label, Value>),
+    RecordLit(HashMap<Label, Value>),
     UnionType(HashMap<Label, Option<Value>>),
     UnionConstructor(Label, HashMap<Label, Option<Value>>),
     UnionLit(Label, Value, HashMap<Label, Option<Value>>),
-    // Invariant: this must not contain interpolations that are themselves TextLits, and
+    // Invariant: in whnf, this must not contain interpolations that are themselves TextLits, and
     // contiguous text values must be merged.
     TextLit(Vec<InterpolatedTextContents<Value>>),
     Equivalence(Value, Value),
-    // Invariant: this must not contain a value captured by one of the variants above.
+    // Invariant: in whnf, this must not contain a value captured by one of the variants above.
     PartialExpr(ExprF<Value, Normalized>),
 }
 
@@ -53,11 +53,23 @@ impl ValueF {
     pub(crate) fn into_value_with_type(self, t: Value) -> Value {
         Value::from_valuef_and_type(self, t)
     }
-    pub(crate) fn into_value_simple_type(self) -> Value {
-        Value::from_valuef_simple_type(self)
+    pub(crate) fn into_vovf_unevaled(self) -> VoVF {
+        VoVF::ValueF {
+            val: self,
+            form: Form::Unevaled,
+        }
+    }
+    pub(crate) fn into_vovf_whnf(self) -> VoVF {
+        VoVF::ValueF {
+            val: self,
+            form: Form::WHNF,
+        }
     }
-    pub(crate) fn into_vovf(self) -> VoVF {
-        VoVF::ValueF(self)
+    pub(crate) fn into_vovf_nf(self) -> VoVF {
+        VoVF::ValueF {
+            val: self,
+            form: Form::NF,
+        }
     }
 
     /// Convert the value to a fully normalized syntactic expression
@@ -261,7 +273,7 @@ impl ValueF {
 
     /// Apply to a value
     pub fn app(self, v: Value) -> VoVF {
-        self.into_vovf().app(v)
+        self.into_vovf_unevaled().app(v)
     }
 
     pub fn from_builtin(b: Builtin) -> ValueF {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index e044018..a146ec7 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -70,29 +70,29 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
     // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
     let ret = match (b, args.as_slice()) {
         (OptionalNone, [t, r..]) => {
-            Ok((r, EmptyOptionalLit(t.clone()).into_vovf()))
+            Ok((r, EmptyOptionalLit(t.clone()).into_vovf_whnf()))
         }
         (NaturalIsZero, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n == 0).into_vovf())),
+            NaturalLit(n) => Ok((r, BoolLit(*n == 0).into_vovf_nf())),
             _ => Err(()),
         },
         (NaturalEven, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0).into_vovf())),
+            NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0).into_vovf_nf())),
             _ => Err(()),
         },
         (NaturalOdd, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0).into_vovf())),
+            NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0).into_vovf_nf())),
             _ => Err(()),
         },
         (NaturalToInteger, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, IntegerLit(*n as isize).into_vovf())),
+            NaturalLit(n) => Ok((r, IntegerLit(*n as isize).into_vovf_nf())),
             _ => Err(()),
         },
         (NaturalShow, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((
                 r,
                 TextLit(vec![InterpolatedTextContents::Text(n.to_string())])
-                    .into_vovf(),
+                    .into_vovf_nf(),
             )),
             _ => Err(()),
         },
@@ -100,11 +100,11 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             match (&*a.as_whnf(), &*b.as_whnf()) {
                 (NaturalLit(a), NaturalLit(b)) => Ok((
                     r,
-                    NaturalLit(if b > a { b - a } else { 0 }).into_vovf(),
+                    NaturalLit(if b > a { b - a } else { 0 }).into_vovf_nf(),
                 )),
                 (NaturalLit(0), _) => Ok((r, b.clone().into_vovf())),
-                (_, NaturalLit(0)) => Ok((r, NaturalLit(0).into_vovf())),
-                _ if a == b => Ok((r, NaturalLit(0).into_vovf())),
+                (_, NaturalLit(0)) => Ok((r, NaturalLit(0).into_vovf_nf())),
+                _ if a == b => Ok((r, NaturalLit(0).into_vovf_nf())),
                 _ => Err(()),
             }
         }
@@ -118,14 +118,14 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 Ok((
                     r,
                     TextLit(vec![InterpolatedTextContents::Text(s)])
-                        .into_vovf(),
+                        .into_vovf_nf(),
                 ))
             }
             _ => Err(()),
         },
         (IntegerToDouble, [n, r..]) => match &*n.as_whnf() {
             IntegerLit(n) => {
-                Ok((r, DoubleLit(NaiveDouble::from(*n as f64)).into_vovf()))
+                Ok((r, DoubleLit(NaiveDouble::from(*n as f64)).into_vovf_nf()))
             }
             _ => Err(()),
         },
@@ -133,7 +133,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             DoubleLit(n) => Ok((
                 r,
                 TextLit(vec![InterpolatedTextContents::Text(n.to_string())])
-                    .into_vovf(),
+                    .into_vovf_nf(),
             )),
             _ => Err(()),
         },
@@ -149,7 +149,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         Ok((
                             r,
                             TextLit(vec![InterpolatedTextContents::Text(s)])
-                                .into_vovf(),
+                                .into_vovf_nf(),
                         ))
                     }
                     // If there are no interpolations (invariants ensure that when there are no
@@ -165,7 +165,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         Ok((
                             r,
                             TextLit(vec![InterpolatedTextContents::Text(s)])
-                                .into_vovf(),
+                                .into_vovf_nf(),
                         ))
                     }
                     _ => Err(()),
@@ -174,32 +174,39 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             _ => Err(()),
         },
         (ListLength, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(_) => Ok((r, NaturalLit(0).into_vovf())),
-            NEListLit(xs) => Ok((r, NaturalLit(xs.len()).into_vovf())),
+            EmptyListLit(_) => Ok((r, NaturalLit(0).into_vovf_nf())),
+            NEListLit(xs) => Ok((r, NaturalLit(xs.len()).into_vovf_nf())),
             _ => Err(()),
         },
         (ListHead, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()).into_vovf())),
+            EmptyListLit(n) => {
+                Ok((r, EmptyOptionalLit(n.clone()).into_vovf_whnf()))
+            }
             NEListLit(xs) => Ok((
                 r,
-                NEOptionalLit(xs.iter().next().unwrap().clone()).into_vovf(),
+                NEOptionalLit(xs.iter().next().unwrap().clone())
+                    .into_vovf_whnf(),
             )),
             _ => Err(()),
         },
         (ListLast, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()).into_vovf())),
+            EmptyListLit(n) => {
+                Ok((r, EmptyOptionalLit(n.clone()).into_vovf_whnf()))
+            }
             NEListLit(xs) => Ok((
                 r,
                 NEOptionalLit(xs.iter().rev().next().unwrap().clone())
-                    .into_vovf(),
+                    .into_vovf_whnf(),
             )),
             _ => Err(()),
         },
         (ListReverse, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => Ok((r, EmptyListLit(n.clone()).into_vovf())),
+            EmptyListLit(n) => {
+                Ok((r, EmptyListLit(n.clone()).into_vovf_whnf()))
+            }
             NEListLit(xs) => Ok((
                 r,
-                NEListLit(xs.iter().rev().cloned().collect()).into_vovf(),
+                NEListLit(xs.iter().rev().cloned().collect()).into_vovf_whnf(),
             )),
             _ => Err(()),
         },
@@ -211,7 +218,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 Ok((
                     r,
                     EmptyListLit(Value::from_valuef_untyped(RecordType(kts)))
-                        .into_vovf(),
+                        .into_vovf_whnf(),
                 ))
             }
             NEListLit(xs) => {
@@ -229,7 +236,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         Value::from_valuef_untyped(RecordLit(kvs))
                     })
                     .collect();
-                Ok((r, NEListLit(xs).into_vovf()))
+                Ok((r, NEListLit(xs).into_vovf_whnf()))
             }
             _ => Err(()),
         },
@@ -353,13 +360,14 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             }
             v
         }
-        Err(()) => AppliedBuiltin(b, args).into_vovf(),
+        Err(()) => AppliedBuiltin(b, args).into_vovf_whnf(),
     }
 }
 
 pub(crate) fn apply_any(f: Value, a: Value) -> VoVF {
-    let fallback =
-        |f: Value, a: Value| ValueF::PartialExpr(ExprF::App(f, a)).into_vovf();
+    let fallback = |f: Value, a: Value| {
+        ValueF::PartialExpr(ExprF::App(f, a)).into_vovf_whnf()
+    };
 
     let f_borrow = f.as_whnf();
     match &*f_borrow {
@@ -370,7 +378,7 @@ pub(crate) fn apply_any(f: Value, a: Value) -> VoVF {
             apply_builtin(*b, args)
         }
         ValueF::UnionConstructor(l, kts) => {
-            ValueF::UnionLit(l.clone(), a, kts.clone()).into_vovf()
+            ValueF::UnionLit(l.clone(), a, kts.clone()).into_vovf_whnf()
         }
         _ => {
             drop(f_borrow);
@@ -774,11 +782,11 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
     };
 
     match ret {
-        Ret::ValueF(v) => v.into_vovf(),
+        Ret::ValueF(v) => v.into_vovf_whnf(),
         Ret::Value(v) => v.into_vovf(),
         Ret::VoVF(v) => v,
         Ret::ValueRef(v) => v.clone().into_vovf(),
-        Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf(),
+        Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf_whnf(),
     }
 }
 
@@ -788,9 +796,9 @@ pub(crate) fn normalize_whnf(v: ValueF) -> VoVF {
         ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args),
         ValueF::PartialExpr(e) => normalize_one_layer(e),
         ValueF::TextLit(elts) => {
-            ValueF::TextLit(squash_textlit(elts.into_iter())).into_vovf()
+            ValueF::TextLit(squash_textlit(elts.into_iter())).into_vovf_whnf()
         }
         // All other cases are already in WHNF
-        v => v.into_vovf(),
+        v => v.into_vovf_whnf(),
     }
 }
-- 
cgit v1.3.1


From ec349d42703a8a31715cf97b44845ba3dd7a6805 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 22:20:59 +0200
Subject: Propagate type information in Value::app()

---
 dhall/src/core/value.rs      | 23 +++++++++++++++--------
 dhall/src/phase/normalize.rs | 35 ++++++++++++++++-------------------
 dhall/src/phase/typecheck.rs | 10 ++--------
 tests_buffer                 |  1 +
 4 files changed, 34 insertions(+), 35 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index b44dad6..24e2803 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -214,8 +214,18 @@ impl Value {
         self.as_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
-    pub(crate) fn app(&self, v: Value) -> VoVF {
-        apply_any(self.clone(), v)
+    pub(crate) fn app(&self, v: Value) -> Value {
+        let vovf = apply_any(self.clone(), v.clone());
+        match self.as_internal().get_type() {
+            Err(_) => vovf.into_value_untyped(),
+            Ok(t) => match &*t.as_whnf() {
+                ValueF::Pi(x, _, e) => {
+                    let t = e.subst_shift(&x.into(), &v);
+                    vovf.into_value_with_type(t)
+                }
+                _ => unreachable!("Internal type error"),
+            },
+        }
     }
 
     pub(crate) fn get_type(&self) -> Result<Value, TypeError> {
@@ -248,15 +258,12 @@ impl VoVF {
             VoVF::ValueF { val, form } => Value::new(val, form, Some(t)),
         }
     }
-    pub(crate) fn into_value_simple_type(self) -> Value {
-        self.into_value_with_type(Value::from_const(Const::Type))
-    }
 
-    pub(crate) fn app(self, x: Value) -> Self {
-        match self {
+    pub(crate) fn app(self, x: Value) -> VoVF {
+        VoVF::Value(match self {
             VoVF::Value(v) => v.app(x),
             VoVF::ValueF { val, .. } => val.into_value_untyped().app(x),
-        }
+        })
     }
 }
 
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index a146ec7..e4a0c5b 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -34,7 +34,6 @@ macro_rules! make_closure {
     (List $($rest:tt)*) => {
         Value::from_builtin(Builtin::List)
             .app(make_closure!($($rest)*))
-            .into_value_simple_type()
     };
     (Some($($rest:tt)*)) => {
         ValueF::NEOptionalLit(make_closure!($($rest)*))
@@ -251,9 +250,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 }
             }
             _ => {
-                let list_t = Value::from_builtin(List)
-                    .app(t.clone())
-                    .into_value_simple_type();
+                let list_t = Value::from_builtin(List).app(t.clone());
                 Ok((
                     r,
                     f.app(list_t.clone())
@@ -269,18 +266,19 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         .app(
                             EmptyListLit(t.clone())
                                 .into_value_with_type(list_t),
-                        ),
+                        )
+                        .into_vovf(),
                 ))
             }
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() {
             EmptyListLit(_) => Ok((r, nil.clone().into_vovf())),
             NEListLit(xs) => {
-                let mut v = nil.clone().into_vovf();
+                let mut v = nil.clone();
                 for x in xs.iter().cloned().rev() {
-                    v = cons.app(x).app(v.into_value_untyped());
+                    v = cons.app(x).app(v);
                 }
-                Ok((r, v))
+                Ok((r, v.into_vovf()))
             }
             _ => Err(()),
         },
@@ -295,9 +293,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 }
             }
             _ => {
-                let optional_t = Value::from_builtin(Optional)
-                    .app(t.clone())
-                    .into_value_simple_type();
+                let optional_t = Value::from_builtin(Optional).app(t.clone());
                 Ok((
                     r,
                     f.app(optional_t.clone())
@@ -305,13 +301,14 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         .app(
                             EmptyOptionalLit(t.clone())
                                 .into_value_with_type(optional_t),
-                        ),
+                        )
+                        .into_vovf(),
                 ))
             }
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
             EmptyOptionalLit(_) => Ok((r, nothing.clone().into_vovf())),
-            NEOptionalLit(x) => Ok((r, just.app(x.clone()))),
+            NEOptionalLit(x) => Ok((r, just.app(x.clone()).into_vovf())),
             _ => Err(()),
         },
         (NaturalBuild, [f, r..]) => match &*f.as_whnf() {
@@ -331,7 +328,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                     .app(
                         NaturalLit(0)
                             .into_value_with_type(Value::from_builtin(Natural)),
-                    ),
+                    )
+                    .into_vovf(),
             )),
         },
         (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() {
@@ -344,9 +342,8 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                     )
                     .app(t.clone())
                     .app(succ.clone())
-                    .app(zero.clone())
-                    .into_value_with_type(t.clone());
-                Ok((r, succ.app(fold)))
+                    .app(zero.clone());
+                Ok((r, succ.app(fold).into_vovf()))
             }
             _ => Err(()),
         },
@@ -643,7 +640,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
         ExprF::Lam(x, t, e) => Ret::ValueF(Lam(x.into(), t, e)),
         ExprF::Pi(x, t, e) => Ret::ValueF(Pi(x.into(), t, e)),
         ExprF::Let(x, _, v, b) => Ret::Value(b.subst_shift(&x.into(), &v)),
-        ExprF::App(v, a) => Ret::VoVF(v.app(a)),
+        ExprF::App(v, a) => Ret::Value(v.app(a)),
         ExprF::Builtin(b) => Ret::ValueF(ValueF::from_builtin(b)),
         ExprF::Const(c) => Ret::ValueF(ValueF::Const(c)),
         ExprF::BoolLit(b) => Ret::ValueF(BoolLit(b)),
@@ -765,7 +762,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
                     }
                 },
                 (RecordLit(kvs), UnionLit(l, v, _)) => match kvs.get(l) {
-                    Some(h) => Ret::VoVF(h.app(v.clone())),
+                    Some(h) => Ret::Value(h.app(v.clone())),
                     None => {
                         drop(handlers_borrow);
                         drop(variant_borrow);
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 4abc314..abe05a3 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -455,11 +455,7 @@ fn type_last_layer(
                 return mkerr(InvalidListType(t));
             }
 
-            RetTypeOnly(
-                ValueF::from_builtin(dhall_syntax::Builtin::List)
-                    .app(t)
-                    .into_value_simple_type(),
-            )
+            RetTypeOnly(Value::from_builtin(dhall_syntax::Builtin::List).app(t))
         }
         SomeLit(x) => {
             let t = x.get_type()?;
@@ -468,9 +464,7 @@ fn type_last_layer(
             }
 
             RetTypeOnly(
-                Value::from_builtin(dhall_syntax::Builtin::Optional)
-                    .app(t)
-                    .into_value_simple_type(),
+                Value::from_builtin(dhall_syntax::Builtin::Optional).app(t),
             )
         }
         RecordType(kts) => RetWhole(tck_record_type(
diff --git a/tests_buffer b/tests_buffer
index c6366ba..15dc9c5 100644
--- a/tests_buffer
+++ b/tests_buffer
@@ -41,5 +41,6 @@ failure/
     merge {x=...,y=...} <x:T>.x
     MergeBoolIsNotUnion merge x True
     MergeOptionalIsNotUnion merge x (Some 1)
+    SortInLet let x = Sort in 1
 
 equivalence:
-- 
cgit v1.3.1


From 8e68396e9fe3751bcf8bcfd68301ca7fea836787 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 22:35:53 +0200
Subject: Use Ret in apply_builtin

---
 dhall/src/core/valuef.rs     |   6 --
 dhall/src/phase/normalize.rs | 191 +++++++++++++++++++++++--------------------
 2 files changed, 101 insertions(+), 96 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index db8a284..316238c 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -65,12 +65,6 @@ impl ValueF {
             form: Form::WHNF,
         }
     }
-    pub(crate) fn into_vovf_nf(self) -> VoVF {
-        VoVF::ValueF {
-            val: self,
-            form: Form::NF,
-        }
-    }
 
     /// Convert the value to a fully normalized syntactic expression
     pub(crate) fn normalize_to_expr(&self) -> NormalizedSubExpr {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index e4a0c5b..0c4e185 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -10,6 +10,25 @@ use crate::core::valuef::ValueF;
 use crate::core::var::{Shift, Subst};
 use crate::phase::Normalized;
 
+// Small helper enum to avoid repetition
+enum Ret<'a> {
+    ValueF(ValueF),
+    Value(Value),
+    ValueRef(&'a Value),
+    Expr(ExprF<Value, Normalized>),
+}
+
+impl<'a> Ret<'a> {
+    fn into_vovf_whnf(self) -> VoVF {
+        match self {
+            Ret::ValueF(v) => v.into_vovf_whnf(),
+            Ret::Value(v) => v.into_vovf(),
+            Ret::ValueRef(v) => v.clone().into_vovf(),
+            Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf_whnf(),
+        }
+    }
+}
+
 // Ad-hoc macro to help construct closures
 macro_rules! make_closure {
     (#$var:ident) => { $var.clone() };
@@ -69,29 +88,30 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
     // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
     let ret = match (b, args.as_slice()) {
         (OptionalNone, [t, r..]) => {
-            Ok((r, EmptyOptionalLit(t.clone()).into_vovf_whnf()))
+            Ok((r, Ret::ValueF(EmptyOptionalLit(t.clone()))))
         }
         (NaturalIsZero, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n == 0).into_vovf_nf())),
+            NaturalLit(n) => Ok((r, Ret::ValueF(BoolLit(*n == 0)))),
             _ => Err(()),
         },
         (NaturalEven, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0).into_vovf_nf())),
+            NaturalLit(n) => Ok((r, Ret::ValueF(BoolLit(*n % 2 == 0)))),
             _ => Err(()),
         },
         (NaturalOdd, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0).into_vovf_nf())),
+            NaturalLit(n) => Ok((r, Ret::ValueF(BoolLit(*n % 2 != 0)))),
             _ => Err(()),
         },
         (NaturalToInteger, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, IntegerLit(*n as isize).into_vovf_nf())),
+            NaturalLit(n) => Ok((r, Ret::ValueF(IntegerLit(*n as isize)))),
             _ => Err(()),
         },
         (NaturalShow, [n, r..]) => match &*n.as_whnf() {
             NaturalLit(n) => Ok((
                 r,
-                TextLit(vec![InterpolatedTextContents::Text(n.to_string())])
-                    .into_vovf_nf(),
+                Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(
+                    n.to_string(),
+                )])),
             )),
             _ => Err(()),
         },
@@ -99,11 +119,11 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             match (&*a.as_whnf(), &*b.as_whnf()) {
                 (NaturalLit(a), NaturalLit(b)) => Ok((
                     r,
-                    NaturalLit(if b > a { b - a } else { 0 }).into_vovf_nf(),
+                    Ret::ValueF(NaturalLit(if b > a { b - a } else { 0 })),
                 )),
-                (NaturalLit(0), _) => Ok((r, b.clone().into_vovf())),
-                (_, NaturalLit(0)) => Ok((r, NaturalLit(0).into_vovf_nf())),
-                _ if a == b => Ok((r, NaturalLit(0).into_vovf_nf())),
+                (NaturalLit(0), _) => Ok((r, Ret::ValueRef(b))),
+                (_, NaturalLit(0)) => Ok((r, Ret::ValueF(NaturalLit(0)))),
+                _ if a == b => Ok((r, Ret::ValueF(NaturalLit(0)))),
                 _ => Err(()),
             }
         }
@@ -116,23 +136,25 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 };
                 Ok((
                     r,
-                    TextLit(vec![InterpolatedTextContents::Text(s)])
-                        .into_vovf_nf(),
+                    Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(
+                        s,
+                    )])),
                 ))
             }
             _ => Err(()),
         },
         (IntegerToDouble, [n, r..]) => match &*n.as_whnf() {
             IntegerLit(n) => {
-                Ok((r, DoubleLit(NaiveDouble::from(*n as f64)).into_vovf_nf()))
+                Ok((r, Ret::ValueF(DoubleLit(NaiveDouble::from(*n as f64)))))
             }
             _ => Err(()),
         },
         (DoubleShow, [n, r..]) => match &*n.as_whnf() {
             DoubleLit(n) => Ok((
                 r,
-                TextLit(vec![InterpolatedTextContents::Text(n.to_string())])
-                    .into_vovf_nf(),
+                Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(
+                    n.to_string(),
+                )])),
             )),
             _ => Err(()),
         },
@@ -147,8 +169,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         let s = txt.to_string();
                         Ok((
                             r,
-                            TextLit(vec![InterpolatedTextContents::Text(s)])
-                                .into_vovf_nf(),
+                            Ret::ValueF(TextLit(vec![
+                                InterpolatedTextContents::Text(s),
+                            ])),
                         ))
                     }
                     // If there are no interpolations (invariants ensure that when there are no
@@ -163,8 +186,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         let s = txt.to_string();
                         Ok((
                             r,
-                            TextLit(vec![InterpolatedTextContents::Text(s)])
-                                .into_vovf_nf(),
+                            Ret::ValueF(TextLit(vec![
+                                InterpolatedTextContents::Text(s),
+                            ])),
                         ))
                     }
                     _ => Err(()),
@@ -173,39 +197,37 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             _ => Err(()),
         },
         (ListLength, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(_) => Ok((r, NaturalLit(0).into_vovf_nf())),
-            NEListLit(xs) => Ok((r, NaturalLit(xs.len()).into_vovf_nf())),
+            EmptyListLit(_) => Ok((r, Ret::ValueF(NaturalLit(0)))),
+            NEListLit(xs) => Ok((r, Ret::ValueF(NaturalLit(xs.len())))),
             _ => Err(()),
         },
         (ListHead, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(n) => {
-                Ok((r, EmptyOptionalLit(n.clone()).into_vovf_whnf()))
+                Ok((r, Ret::ValueF(EmptyOptionalLit(n.clone()))))
             }
             NEListLit(xs) => Ok((
                 r,
-                NEOptionalLit(xs.iter().next().unwrap().clone())
-                    .into_vovf_whnf(),
+                Ret::ValueF(NEOptionalLit(xs.iter().next().unwrap().clone())),
             )),
             _ => Err(()),
         },
         (ListLast, [_, l, r..]) => match &*l.as_whnf() {
             EmptyListLit(n) => {
-                Ok((r, EmptyOptionalLit(n.clone()).into_vovf_whnf()))
+                Ok((r, Ret::ValueF(EmptyOptionalLit(n.clone()))))
             }
             NEListLit(xs) => Ok((
                 r,
-                NEOptionalLit(xs.iter().rev().next().unwrap().clone())
-                    .into_vovf_whnf(),
+                Ret::ValueF(NEOptionalLit(
+                    xs.iter().rev().next().unwrap().clone(),
+                )),
             )),
             _ => Err(()),
         },
         (ListReverse, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => {
-                Ok((r, EmptyListLit(n.clone()).into_vovf_whnf()))
-            }
+            EmptyListLit(n) => Ok((r, Ret::ValueF(EmptyListLit(n.clone())))),
             NEListLit(xs) => Ok((
                 r,
-                NEListLit(xs.iter().rev().cloned().collect()).into_vovf_whnf(),
+                Ret::ValueF(NEListLit(xs.iter().rev().cloned().collect())),
             )),
             _ => Err(()),
         },
@@ -216,8 +238,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 kts.insert("value".into(), t.clone());
                 Ok((
                     r,
-                    EmptyListLit(Value::from_valuef_untyped(RecordType(kts)))
-                        .into_vovf_whnf(),
+                    Ret::ValueF(EmptyListLit(Value::from_valuef_untyped(
+                        RecordType(kts),
+                    ))),
                 ))
             }
             NEListLit(xs) => {
@@ -235,7 +258,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                         Value::from_valuef_untyped(RecordLit(kvs))
                     })
                     .collect();
-                Ok((r, NEListLit(xs).into_vovf_whnf()))
+                Ok((r, Ret::ValueF(NEListLit(xs))))
             }
             _ => Err(()),
         },
@@ -243,7 +266,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             // fold/build fusion
             ValueF::AppliedBuiltin(ListFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].clone().into_vovf()))
+                    Ok((r, Ret::Value(args[1].clone())))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -253,32 +276,33 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 let list_t = Value::from_builtin(List).app(t.clone());
                 Ok((
                     r,
-                    f.app(list_t.clone())
-                        .app({
-                            // Move `t` under new `x` variable
-                            let t1 = t.under_binder(Label::from("x"));
-                            make_closure!(
-                                λ(x : #t) ->
-                                λ(xs : List #t1) ->
-                                [ var(x, 1) ] # var(xs, 0)
-                            )
-                        })
-                        .app(
-                            EmptyListLit(t.clone())
-                                .into_value_with_type(list_t),
-                        )
-                        .into_vovf(),
+                    Ret::Value(
+                        f.app(list_t.clone())
+                            .app({
+                                // Move `t` under new `x` variable
+                                let t1 = t.under_binder(Label::from("x"));
+                                make_closure!(
+                                    λ(x : #t) ->
+                                    λ(xs : List #t1) ->
+                                    [ var(x, 1) ] # var(xs, 0)
+                                )
+                            })
+                            .app(
+                                EmptyListLit(t.clone())
+                                    .into_value_with_type(list_t),
+                            ),
+                    ),
                 ))
             }
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() {
-            EmptyListLit(_) => Ok((r, nil.clone().into_vovf())),
+            EmptyListLit(_) => Ok((r, Ret::ValueRef(nil))),
             NEListLit(xs) => {
                 let mut v = nil.clone();
                 for x in xs.iter().cloned().rev() {
                     v = cons.app(x).app(v);
                 }
-                Ok((r, v.into_vovf()))
+                Ok((r, Ret::Value(v)))
             }
             _ => Err(()),
         },
@@ -286,7 +310,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             // fold/build fusion
             ValueF::AppliedBuiltin(OptionalFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, args[1].clone().into_vovf()))
+                    Ok((r, Ret::Value(args[1].clone())))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -296,26 +320,27 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 let optional_t = Value::from_builtin(Optional).app(t.clone());
                 Ok((
                     r,
-                    f.app(optional_t.clone())
-                        .app(make_closure!(λ(x: #t) -> Some(var(x, 0))))
-                        .app(
-                            EmptyOptionalLit(t.clone())
-                                .into_value_with_type(optional_t),
-                        )
-                        .into_vovf(),
+                    Ret::Value(
+                        f.app(optional_t.clone())
+                            .app(make_closure!(λ(x: #t) -> Some(var(x, 0))))
+                            .app(
+                                EmptyOptionalLit(t.clone())
+                                    .into_value_with_type(optional_t),
+                            ),
+                    ),
                 ))
             }
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
-            EmptyOptionalLit(_) => Ok((r, nothing.clone().into_vovf())),
-            NEOptionalLit(x) => Ok((r, just.app(x.clone()).into_vovf())),
+            EmptyOptionalLit(_) => Ok((r, Ret::ValueRef(nothing))),
+            NEOptionalLit(x) => Ok((r, Ret::Value(just.app(x.clone())))),
             _ => Err(()),
         },
         (NaturalBuild, [f, r..]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(NaturalFold, args) => {
                 if !args.is_empty() {
-                    Ok((r, args[0].clone().into_vovf()))
+                    Ok((r, Ret::Value(args[0].clone())))
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -323,17 +348,17 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             }
             _ => Ok((
                 r,
-                f.app(Value::from_builtin(Natural))
-                    .app(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
-                    .app(
-                        NaturalLit(0)
-                            .into_value_with_type(Value::from_builtin(Natural)),
-                    )
-                    .into_vovf(),
+                Ret::Value(
+                    f.app(Value::from_builtin(Natural))
+                        .app(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
+                        .app(NaturalLit(0).into_value_with_type(
+                            Value::from_builtin(Natural),
+                        )),
+                ),
             )),
         },
         (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() {
-            NaturalLit(0) => Ok((r, zero.clone().into_vovf())),
+            NaturalLit(0) => Ok((r, Ret::ValueRef(zero))),
             NaturalLit(n) => {
                 let fold = Value::from_builtin(NaturalFold)
                     .app(
@@ -343,14 +368,15 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                     .app(t.clone())
                     .app(succ.clone())
                     .app(zero.clone());
-                Ok((r, succ.app(fold).into_vovf()))
+                Ok((r, Ret::Value(succ.app(fold))))
             }
             _ => Err(()),
         },
         _ => Err(()),
     };
     match ret {
-        Ok((unconsumed_args, mut v)) => {
+        Ok((unconsumed_args, ret)) => {
+            let mut v = ret.into_vovf_whnf();
             let n_consumed_args = args.len() - unconsumed_args.len();
             for x in args.into_iter().skip(n_consumed_args) {
                 v = v.app(x);
@@ -485,15 +511,6 @@ where
     kvs
 }
 
-// Small helper enum to avoid repetition
-enum Ret<'a> {
-    ValueF(ValueF),
-    Value(Value),
-    VoVF(VoVF),
-    ValueRef(&'a Value),
-    Expr(ExprF<Value, Normalized>),
-}
-
 fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
     use BinOp::{
         BoolAnd, BoolEQ, BoolNE, BoolOr, Equivalence, ListAppend, NaturalPlus,
@@ -778,13 +795,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
         }
     };
 
-    match ret {
-        Ret::ValueF(v) => v.into_vovf_whnf(),
-        Ret::Value(v) => v.into_vovf(),
-        Ret::VoVF(v) => v,
-        Ret::ValueRef(v) => v.clone().into_vovf(),
-        Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf_whnf(),
-    }
+    ret.into_vovf_whnf()
 }
 
 /// Normalize a ValueF into WHNF
-- 
cgit v1.3.1


From 6c006e122a050ebbe76c8c566e559bbf9f2301a7 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 20 Aug 2019 23:06:14 +0200
Subject: Reduce API surface of dhall crate

---
 dhall/src/core/value.rs  | 13 +++++--------
 dhall/src/core/valuef.rs | 15 ++-------------
 dhall/src/phase/mod.rs   |  6 +++---
 3 files changed, 10 insertions(+), 24 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 24e2803..e1623a8 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -12,7 +12,7 @@ use crate::phase::typecheck::{builtin_to_value, const_to_value};
 use crate::phase::{NormalizedSubExpr, Typed};
 
 #[derive(Debug, Clone, Copy)]
-pub enum Form {
+pub(crate) enum Form {
     /// No constraints; expression may not be normalized at all.
     Unevaled,
     /// Weak Head Normal Form, i.e. normalized up to the first constructor, but subexpressions may
@@ -41,13 +41,13 @@ struct ValueInternal {
 /// sharing computation automatically. Uses a RefCell to share computation.
 /// Can optionally store a type from typechecking to preserve type information.
 #[derive(Clone)]
-pub struct Value(Rc<RefCell<ValueInternal>>);
+pub(crate) struct Value(Rc<RefCell<ValueInternal>>);
 
 /// When a function needs to return either a freshly created ValueF or an existing Value, but
 /// doesn't want to convert both to the same thing, either to avoid unnecessary allocations or to
 /// avoid loss of typ information.
 #[derive(Debug, Clone)]
-pub enum VoVF {
+pub(crate) enum VoVF {
     Value(Value),
     ValueF { val: ValueF, form: Form },
 }
@@ -111,10 +111,7 @@ impl Value {
     pub(crate) fn from_const(c: Const) -> Self {
         const_to_value(c)
     }
-    pub fn const_type() -> Self {
-        Value::from_const(Const::Type)
-    }
-    pub fn from_builtin(b: Builtin) -> Self {
+    pub(crate) fn from_builtin(b: Builtin) -> Self {
         builtin_to_value(b)
     }
 
@@ -234,7 +231,7 @@ impl Value {
 }
 
 impl VoVF {
-    pub fn into_whnf(self) -> ValueF {
+    pub(crate) fn into_whnf(self) -> ValueF {
         match self {
             VoVF::Value(v) => v.to_whnf(),
             VoVF::ValueF {
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 316238c..42606a9 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -15,7 +15,7 @@ use crate::phase::{Normalized, NormalizedSubExpr};
 /// alpha-equivalence (renaming of bound variables) and beta-equivalence (normalization). It will
 /// recursively normalize as needed.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub enum ValueF {
+pub(crate) enum ValueF {
     /// Closures
     Lam(AlphaLabel, Value, Value),
     Pi(AlphaLabel, Value, Value),
@@ -53,12 +53,6 @@ impl ValueF {
     pub(crate) fn into_value_with_type(self, t: Value) -> Value {
         Value::from_valuef_and_type(self, t)
     }
-    pub(crate) fn into_vovf_unevaled(self) -> VoVF {
-        VoVF::ValueF {
-            val: self,
-            form: Form::Unevaled,
-        }
-    }
     pub(crate) fn into_vovf_whnf(self) -> VoVF {
         VoVF::ValueF {
             val: self,
@@ -265,12 +259,7 @@ impl ValueF {
         }
     }
 
-    /// Apply to a value
-    pub fn app(self, v: Value) -> VoVF {
-        self.into_vovf_unevaled().app(v)
-    }
-
-    pub fn from_builtin(b: Builtin) -> ValueF {
+    pub(crate) fn from_builtin(b: Builtin) -> ValueF {
         ValueF::AppliedBuiltin(b, vec![])
     }
 }
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index b5b7b64..ecf04e9 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -92,13 +92,13 @@ impl Typed {
     pub(crate) fn from_const(c: Const) -> Self {
         Typed(Value::from_const(c))
     }
-    pub fn from_valuef_and_type(v: ValueF, t: Typed) -> Self {
+    pub(crate) fn from_valuef_and_type(v: ValueF, t: Typed) -> Self {
         Typed(Value::from_valuef_and_type(v, t.into_value()))
     }
     pub(crate) fn from_value(th: Value) -> Self {
         Typed(th)
     }
-    pub fn const_type() -> Self {
+    pub(crate) fn const_type() -> Self {
         Typed::from_const(Const::Type)
     }
 
@@ -108,7 +108,7 @@ impl Typed {
     pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.0.to_expr_alpha()
     }
-    pub fn to_value(&self) -> Value {
+    pub(crate) fn to_value(&self) -> Value {
         self.0.clone()
     }
     pub(crate) fn into_value(self) -> Value {
-- 
cgit v1.3.1


From e8a9178ebe4860a8a00a6ec8f77b661fdad84890 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Wed, 21 Aug 2019 17:40:56 +0200
Subject: Don't use take_mut::take lightly since normalize_whnf might panic

---
 dhall/src/core/value.rs | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index e1623a8..69d372a 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -61,16 +61,25 @@ impl ValueInternal {
     }
 
     fn normalize_whnf(&mut self) {
-        take_mut::take(self, |vint| match &vint.form {
-            Unevaled => ValueInternal {
-                form: WHNF,
-                // TODO: thunk chaining
-                value: normalize_whnf(vint.value).into_whnf(),
-                ty: vint.ty,
+        take_mut::take_or_recover(
+            self,
+            // Dummy value in case the other closure panics
+            || ValueInternal {
+                form: Unevaled,
+                value: ValueF::Const(Const::Type),
+                ty: None,
             },
-            // Already in WHNF
-            WHNF | NF => vint,
-        })
+            |vint| match &vint.form {
+                Unevaled => ValueInternal {
+                    form: WHNF,
+                    // TODO: thunk chaining
+                    value: normalize_whnf(vint.value).into_whnf(),
+                    ty: vint.ty,
+                },
+                // Already in WHNF
+                WHNF | NF => vint,
+            },
+        )
     }
     fn normalize_nf(&mut self) {
         match self.form {
-- 
cgit v1.3.1


From 98399997cf289d802fbed674558665547cf73d59 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 25 Aug 2019 16:09:55 +0200
Subject: Keep type information through normalization

---
 dhall/src/core/value.rs      |  39 ++++++---
 dhall/src/phase/normalize.rs | 200 ++++++++++++++++++++++++++++---------------
 dhall/src/phase/typecheck.rs |  21 ++---
 tests_buffer                 |   3 +
 4 files changed, 173 insertions(+), 90 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 69d372a..6f9f78a 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -70,12 +70,25 @@ impl ValueInternal {
                 ty: None,
             },
             |vint| match &vint.form {
-                Unevaled => ValueInternal {
-                    form: WHNF,
-                    // TODO: thunk chaining
-                    value: normalize_whnf(vint.value).into_whnf(),
-                    ty: vint.ty,
-                },
+                Unevaled => {
+                    let (value, ty) = (vint.value, vint.ty);
+                    let vovf = normalize_whnf(value, ty.as_ref());
+                    // let was_value = if let VoVF::Value(_) = &vovf {
+                    //     true
+                    // } else {
+                    //     false
+                    // };
+                    let (new_val, _new_ty) =
+                        vovf.into_whnf_and_type(ty.as_ref());
+                    // if was_value {
+                    //     debug_assert_eq!(ty, new_ty);
+                    // }
+                    ValueInternal {
+                        form: WHNF,
+                        value: new_val,
+                        ty: ty,
+                    }
+                }
                 // Already in WHNF
                 WHNF | NF => vint,
             },
@@ -221,7 +234,8 @@ impl Value {
     }
 
     pub(crate) fn app(&self, v: Value) -> Value {
-        let vovf = apply_any(self.clone(), v.clone());
+        let ty = self.get_type().ok();
+        let vovf = apply_any(self.clone(), v.clone(), ty.as_ref());
         match self.as_internal().get_type() {
             Err(_) => vovf.into_value_untyped(),
             Ok(t) => match &*t.as_whnf() {
@@ -240,15 +254,18 @@ impl Value {
 }
 
 impl VoVF {
-    pub(crate) fn into_whnf(self) -> ValueF {
+    pub(crate) fn into_whnf_and_type(
+        self,
+        ty: Option<&Value>,
+    ) -> (ValueF, Option<Value>) {
         match self {
-            VoVF::Value(v) => v.to_whnf(),
             VoVF::ValueF {
                 val,
                 form: Unevaled,
-            } => normalize_whnf(val).into_whnf(),
+            } => normalize_whnf(val, ty).into_whnf_and_type(ty),
             // Already at lest in WHNF
-            VoVF::ValueF { val, .. } => val,
+            VoVF::ValueF { val, .. } => (val, None),
+            VoVF::Value(v) => (v.to_whnf(), v.get_type().ok()),
         }
     }
     pub(crate) fn into_value_untyped(self) -> Value {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index c8f5bc2..5743b0d 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -1,5 +1,6 @@
 use std::collections::HashMap;
 
+use dhall_syntax::Const::Type;
 use dhall_syntax::{
     BinOp, Builtin, ExprF, InterpolatedText, InterpolatedTextContents, Label,
     NaiveDouble,
@@ -7,7 +8,7 @@ use dhall_syntax::{
 
 use crate::core::value::{Value, VoVF};
 use crate::core::valuef::ValueF;
-use crate::core::var::{Shift, Subst};
+use crate::core::var::{AlphaLabel, Shift, Subst};
 use crate::phase::Normalized;
 
 // Small helper enum to avoid repetition
@@ -32,21 +33,24 @@ impl<'a> Ret<'a> {
 // Ad-hoc macro to help construct closures
 macro_rules! make_closure {
     (#$var:ident) => { $var.clone() };
-    (var($var:ident, $n:expr)) => {{
+    (var($var:ident, $n:expr, $($ty:tt)*)) => {{
         let var = crate::core::var::AlphaVar::from_var_and_alpha(
             Label::from(stringify!($var)).into(),
             $n
         );
-        ValueF::Var(var).into_value_untyped()
+        ValueF::Var(var)
+            .into_value_with_type(make_closure!($($ty)*))
     }};
     // Warning: assumes that $ty, as a dhall value, has type `Type`
-    (λ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
-        ValueF::Lam(
-            Label::from(stringify!($var)).into(),
-            make_closure!($($ty)*),
-            make_closure!($($rest)*),
-        ).into_value_untyped()
-    };
+    (λ($var:ident : $($ty:tt)*) -> $($body:tt)*) => {{
+        let var: AlphaLabel = Label::from(stringify!($var)).into();
+        let ty = make_closure!($($ty)*);
+        let body = make_closure!($($body)*);
+        let body_ty = body.get_type().expect("Internal type error");
+        let lam_ty = ValueF::Pi(var.clone(), ty.clone(), body_ty)
+            .into_value_with_type(Value::from_const(Type));
+        ValueF::Lam(var, ty, body).into_value_with_type(lam_ty)
+    }};
     (Natural) => {
         Value::from_builtin(Builtin::Natural)
     };
@@ -54,10 +58,12 @@ macro_rules! make_closure {
         Value::from_builtin(Builtin::List)
             .app(make_closure!($($rest)*))
     };
-    (Some($($rest:tt)*)) => {
-        ValueF::NEOptionalLit(make_closure!($($rest)*))
-            .into_value_untyped()
-    };
+    (Some($($rest:tt)*)) => {{
+        let v = make_closure!($($rest)*);
+        let v_type = v.get_type().expect("Internal type error");
+        ValueF::NEOptionalLit(v)
+            .into_value_with_type(v_type)
+    }};
     (1 + $($rest:tt)*) => {
         ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::NaturalPlus,
@@ -70,18 +76,25 @@ macro_rules! make_closure {
             make_closure!(Natural)
         )
     };
-    ([ $($head:tt)* ] # $($tail:tt)*) => {
+    ([ $($head:tt)* ] # $($tail:tt)*) => {{
+        let head = make_closure!($($head)*);
+        let tail = make_closure!($($tail)*);
+        let list_type = tail.get_type().expect("Internal type error");
         ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::ListAppend,
-            ValueF::NEListLit(vec![make_closure!($($head)*)])
-                .into_value_untyped(),
-            make_closure!($($tail)*),
-        )).into_value_untyped()
-    };
+            ValueF::NEListLit(vec![head])
+                .into_value_with_type(list_type.clone()),
+            tail,
+        )).into_value_with_type(list_type)
+    }};
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
+pub(crate) fn apply_builtin(
+    b: Builtin,
+    args: Vec<Value>,
+    _ty: Option<&Value>,
+) -> VoVF {
     use dhall_syntax::Builtin::*;
     use ValueF::*;
 
@@ -231,37 +244,60 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
             )),
             _ => Err(()),
         },
-        (ListIndexed, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(t) => {
-                let mut kts = HashMap::new();
-                kts.insert("index".into(), Value::from_builtin(Natural));
-                kts.insert("value".into(), t.clone());
-                Ok((
-                    r,
-                    Ret::ValueF(EmptyListLit(Value::from_valuef_untyped(
+        (ListIndexed, [_, l, r..]) => {
+            let l_whnf = l.as_whnf();
+            match &*l_whnf {
+                EmptyListLit(_) | NEListLit(_) => {
+                    // Extract the type of the list elements
+                    let t = match &*l_whnf {
+                        EmptyListLit(t) => t.clone(),
+                        NEListLit(xs) => {
+                            xs[0].get_type().expect("Internal type error")
+                        }
+                        _ => unreachable!(),
+                    };
+
+                    // Construct the returned record type: { index: Natural, value: t }
+                    let mut kts = HashMap::new();
+                    kts.insert("index".into(), Value::from_builtin(Natural));
+                    kts.insert("value".into(), t.clone());
+                    let t = Value::from_valuef_and_type(
                         RecordType(kts),
-                    ))),
-                ))
-            }
-            NEListLit(xs) => {
-                let xs = xs
-                    .iter()
-                    .enumerate()
-                    .map(|(i, e)| {
-                        let i = NaturalLit(i);
-                        let mut kvs = HashMap::new();
-                        kvs.insert(
-                            "index".into(),
-                            Value::from_valuef_untyped(i),
-                        );
-                        kvs.insert("value".into(), e.clone());
-                        Value::from_valuef_untyped(RecordLit(kvs))
-                    })
-                    .collect();
-                Ok((r, Ret::ValueF(NEListLit(xs))))
+                        Value::from_const(Type),
+                    );
+
+                    // Construct the new list, with added indices
+                    let list = match &*l_whnf {
+                        EmptyListLit(_) => EmptyListLit(t),
+                        NEListLit(xs) => NEListLit(
+                            xs.iter()
+                                .enumerate()
+                                .map(|(i, e)| {
+                                    let mut kvs = HashMap::new();
+                                    kvs.insert(
+                                        "index".into(),
+                                        Value::from_valuef_and_type(
+                                            NaturalLit(i),
+                                            Value::from_builtin(
+                                                Builtin::Natural,
+                                            ),
+                                        ),
+                                    );
+                                    kvs.insert("value".into(), e.clone());
+                                    Value::from_valuef_and_type(
+                                        RecordLit(kvs),
+                                        t.clone(),
+                                    )
+                                })
+                                .collect(),
+                        ),
+                        _ => unreachable!(),
+                    };
+                    Ok((r, Ret::ValueF(list)))
+                }
+                _ => Err(()),
             }
-            _ => Err(()),
-        },
+        }
         (ListBuild, [t, f, r..]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(ListFold, args) => {
@@ -279,12 +315,13 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                     Ret::Value(
                         f.app(list_t.clone())
                             .app({
-                                // Move `t` under new `x` variable
+                                // Move `t` under new variables
                                 let t1 = t.under_binder(Label::from("x"));
+                                let t2 = t1.under_binder(Label::from("xs"));
                                 make_closure!(
                                     λ(x : #t) ->
                                     λ(xs : List #t1) ->
-                                    [ var(x, 1) ] # var(xs, 0)
+                                    [ var(x, 1, #t2) ] # var(xs, 0, List #t2)
                                 )
                             })
                             .app(
@@ -322,7 +359,10 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                     r,
                     Ret::Value(
                         f.app(optional_t.clone())
-                            .app(make_closure!(λ(x: #t) -> Some(var(x, 0))))
+                            .app({
+                                let t1 = t.under_binder(Label::from("x"));
+                                make_closure!(λ(x: #t) -> Some(var(x, 0, #t1)))
+                            })
                             .app(
                                 EmptyOptionalLit(t.clone())
                                     .into_value_with_type(optional_t),
@@ -350,7 +390,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
                 r,
                 Ret::Value(
                     f.app(Value::from_builtin(Natural))
-                        .app(make_closure!(λ(x : Natural) -> 1 + var(x, 0)))
+                        .app(make_closure!(
+                            λ(x : Natural) -> 1 + var(x, 0, Natural)
+                        ))
                         .app(NaturalLit(0).into_value_with_type(
                             Value::from_builtin(Natural),
                         )),
@@ -387,7 +429,7 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>) -> VoVF {
     }
 }
 
-pub(crate) fn apply_any(f: Value, a: Value) -> VoVF {
+pub(crate) fn apply_any(f: Value, a: Value, ty: Option<&Value>) -> VoVF {
     let fallback = |f: Value, a: Value| {
         ValueF::PartialExpr(ExprF::App(f, a)).into_vovf_whnf()
     };
@@ -398,7 +440,7 @@ pub(crate) fn apply_any(f: Value, a: Value) -> VoVF {
         ValueF::AppliedBuiltin(b, args) => {
             use std::iter::once;
             let args = args.iter().cloned().chain(once(a.clone())).collect();
-            apply_builtin(*b, args)
+            apply_builtin(*b, args, ty)
         }
         ValueF::UnionConstructor(l, kts) => {
             ValueF::UnionLit(l.clone(), a, kts.clone()).into_vovf_whnf()
@@ -458,14 +500,14 @@ pub(crate) fn merge_maps<K, V, F, Err>(
     mut f: F,
 ) -> Result<HashMap<K, V>, Err>
 where
-    F: FnMut(&V, &V) -> Result<V, Err>,
+    F: FnMut(&K, &V, &V) -> Result<V, Err>,
     K: std::hash::Hash + Eq + Clone,
     V: Clone,
 {
     let mut kvs = HashMap::new();
     for (x, v2) in map2 {
         let newv = if let Some(v1) = map1.get(x) {
-            f(v1, v2)?
+            f(x, v1, v2)?
         } else {
             v2.clone()
         };
@@ -478,14 +520,20 @@ where
     Ok(kvs)
 }
 
-fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
+fn apply_binop<'a>(
+    o: BinOp,
+    x: &'a Value,
+    y: &'a Value,
+    ty: Option<&Value>,
+) -> Option<Ret<'a>> {
     use BinOp::{
         BoolAnd, BoolEQ, BoolNE, BoolOr, Equivalence, ListAppend, NaturalPlus,
         NaturalTimes, RecursiveRecordMerge, RecursiveRecordTypeMerge,
         RightBiasedRecordMerge, TextAppend,
     };
     use ValueF::{
-        BoolLit, EmptyListLit, NEListLit, NaturalLit, RecordLit, TextLit,
+        BoolLit, EmptyListLit, NEListLit, NaturalLit, RecordLit, RecordType,
+        TextLit,
     };
     let x_borrow = x.as_whnf();
     let y_borrow = y.as_whnf();
@@ -570,10 +618,21 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
             Ret::ValueRef(y)
         }
         (RecursiveRecordMerge, RecordLit(kvs1), RecordLit(kvs2)) => {
-            let kvs = merge_maps::<_, _, _, !>(kvs1, kvs2, |v1, v2| {
-                Ok(Value::from_valuef_untyped(ValueF::PartialExpr(
-                    ExprF::BinOp(RecursiveRecordMerge, v1.clone(), v2.clone()),
-                )))
+            let ty = ty.expect("Internal type error");
+            let ty_borrow = ty.as_whnf();
+            let kts = match &*ty_borrow {
+                RecordType(kts) => kts,
+                _ => unreachable!("Internal type error"),
+            };
+            let kvs = merge_maps::<_, _, _, !>(kvs1, kvs2, |k, v1, v2| {
+                Ok(Value::from_valuef_and_type(
+                    ValueF::PartialExpr(ExprF::BinOp(
+                        RecursiveRecordMerge,
+                        v1.clone(),
+                        v2.clone(),
+                    )),
+                    kts.get(k).expect("Internal type error").clone(),
+                ))
             })?;
             Ret::ValueF(RecordLit(kvs))
         }
@@ -586,7 +645,10 @@ fn apply_binop<'a>(o: BinOp, x: &'a Value, y: &'a Value) -> Option<Ret<'a>> {
     })
 }
 
-pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
+pub(crate) fn normalize_one_layer(
+    expr: ExprF<Value, Normalized>,
+    ty: Option<&Value>,
+) -> VoVF {
     use ValueF::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit,
         NEListLit, NEOptionalLit, NaturalLit, RecordLit, TextLit,
@@ -669,7 +731,7 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
                 }
             }
         }
-        ExprF::BinOp(o, ref x, ref y) => match apply_binop(o, x, y) {
+        ExprF::BinOp(o, ref x, ref y) => match apply_binop(o, x, y, ty) {
             Some(ret) => ret,
             None => Ret::Expr(expr),
         },
@@ -746,10 +808,10 @@ pub(crate) fn normalize_one_layer(expr: ExprF<Value, Normalized>) -> VoVF {
 }
 
 /// Normalize a ValueF into WHNF
-pub(crate) fn normalize_whnf(v: ValueF) -> VoVF {
+pub(crate) fn normalize_whnf(v: ValueF, ty: Option<&Value>) -> VoVF {
     match v {
-        ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args),
-        ValueF::PartialExpr(e) => normalize_one_layer(e),
+        ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args, ty),
+        ValueF::PartialExpr(e) => normalize_one_layer(e, ty),
         ValueF::TextLit(elts) => {
             ValueF::TextLit(squash_textlit(elts.into_iter())).into_vovf_whnf()
         }
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 0268b80..270191a 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -307,14 +307,15 @@ fn type_with(
     use dhall_syntax::ExprF::{Annot, Embed, Lam, Let, Pi, Var};
 
     Ok(match e.as_ref() {
-        Lam(x, t, b) => {
-            let tx = type_with(ctx, t.clone())?;
-            let ctx2 = ctx.insert_type(x, tx.clone());
-            let b = type_with(&ctx2, b.clone())?;
-            let v = ValueF::Lam(x.clone().into(), tx.clone(), b.clone());
-            let tb = b.get_type()?;
-            let t = tck_pi_type(ctx, x.clone(), tx, tb)?;
-            Value::from_valuef_and_type(v, t)
+        Lam(var, annot, body) => {
+            let annot = type_with(ctx, annot.clone())?;
+            let ctx2 = ctx.insert_type(var, annot.clone());
+            let body = type_with(&ctx2, body.clone())?;
+            let body_type = body.get_type()?;
+            Value::from_valuef_and_type(
+                ValueF::Lam(var.clone().into(), annot.clone(), body),
+                tck_pi_type(ctx, var.clone(), annot, body_type)?,
+            )
         }
         Pi(x, ta, tb) => {
             let ta = type_with(ctx, ta.clone())?;
@@ -567,7 +568,7 @@ fn type_last_layer(
 
             // Union the two records, prefering
             // the values found in the RHS.
-            let kts = merge_maps::<_, _, _, !>(kts_x, kts_y, |_, r_t| {
+            let kts = merge_maps::<_, _, _, !>(kts_x, kts_y, |_, _, r_t| {
                 Ok(r_t.clone())
             })?;
 
@@ -611,7 +612,7 @@ fn type_last_layer(
                 kts_x,
                 kts_y,
                 // If the Label exists for both records, then we hit the recursive case.
-                |l: &Value, r: &Value| {
+                |_, l: &Value, r: &Value| {
                     type_last_layer(
                         ctx,
                         ExprF::BinOp(
diff --git a/tests_buffer b/tests_buffer
index 511ea49..93eb626 100644
--- a/tests_buffer
+++ b/tests_buffer
@@ -35,6 +35,9 @@ add some of the more complicated Prelude tests back, like List/enumerate
 success/
     regression/
         RecursiveRecordTypeMergeTripleCollision { x : { a : Bool } } ⩓ { x : { b : Bool } } ⩓ { x : { c : Bool } }
+        somehow test that ({ x = { z = 1 } } ∧ { x = { y = 2 } }).x has a type
+        somehow test that the recordtype from List/indexed has a type in both empty and nonempty cases
+        somehow test types added to the Foo/build closures
 failure/
     merge { x = λ(x : Bool) → x } (< x: Bool | y: Natural >.x True)
     merge { x = λ(_ : Bool) → _, y = 1 } < x = True | y >
-- 
cgit v1.3.1


From 80fb5355ea90377492b9863f632c01a808f8aade Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 25 Aug 2019 16:33:12 +0200
Subject: Check consistency of type information

---
 dhall/src/core/value.rs      | 53 +++++++++++++++++++++++---------------------
 dhall/src/phase/normalize.rs |  4 ++--
 2 files changed, 30 insertions(+), 27 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 6f9f78a..7f98826 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -71,22 +71,13 @@ impl ValueInternal {
             },
             |vint| match &vint.form {
                 Unevaled => {
-                    let (value, ty) = (vint.value, vint.ty);
-                    let vovf = normalize_whnf(value, ty.as_ref());
-                    // let was_value = if let VoVF::Value(_) = &vovf {
-                    //     true
-                    // } else {
-                    //     false
-                    // };
-                    let (new_val, _new_ty) =
-                        vovf.into_whnf_and_type(ty.as_ref());
-                    // if was_value {
-                    //     debug_assert_eq!(ty, new_ty);
-                    // }
+                    let new_value =
+                        normalize_whnf(vint.value, vint.ty.as_ref())
+                            .into_whnf(vint.ty.as_ref());
                     ValueInternal {
                         form: WHNF,
-                        value: new_val,
-                        ty: ty,
+                        value: new_value,
+                        ty: vint.ty,
                     }
                 }
                 // Already in WHNF
@@ -254,18 +245,23 @@ impl Value {
 }
 
 impl VoVF {
-    pub(crate) fn into_whnf_and_type(
-        self,
-        ty: Option<&Value>,
-    ) -> (ValueF, Option<Value>) {
+    pub(crate) fn into_whnf(self, ty: Option<&Value>) -> ValueF {
         match self {
             VoVF::ValueF {
                 val,
                 form: Unevaled,
-            } => normalize_whnf(val, ty).into_whnf_and_type(ty),
+            } => normalize_whnf(val, ty).into_whnf(ty),
             // Already at lest in WHNF
-            VoVF::ValueF { val, .. } => (val, None),
-            VoVF::Value(v) => (v.to_whnf(), v.get_type().ok()),
+            VoVF::ValueF { val, .. } => val,
+            VoVF::Value(v) => {
+                let v_ty = v.get_type().ok();
+                debug_assert_eq!(
+                    ty,
+                    v_ty.as_ref(),
+                    "The type recovered from normalization doesn't match the stored type."
+                );
+                v.to_whnf()
+            }
         }
     }
     pub(crate) fn into_value_untyped(self) -> Value {
@@ -274,11 +270,18 @@ impl VoVF {
             VoVF::ValueF { val, form } => Value::new(val, form, None),
         }
     }
-    pub(crate) fn into_value_with_type(self, t: Value) -> Value {
+    pub(crate) fn into_value_with_type(self, ty: Value) -> Value {
         match self {
-            // TODO: check type with debug_assert ?
-            VoVF::Value(v) => v,
-            VoVF::ValueF { val, form } => Value::new(val, form, Some(t)),
+            VoVF::Value(v) => {
+                let v_ty = v.get_type().ok();
+                debug_assert_eq!(
+                    Some(&ty),
+                    v_ty.as_ref(),
+                    "The type recovered from normalization doesn't match the stored type."
+                );
+                v
+            }
+            VoVF::ValueF { val, form } => Value::new(val, form, Some(ty)),
         }
     }
 
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 5743b0d..fe99696 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -61,8 +61,8 @@ macro_rules! make_closure {
     (Some($($rest:tt)*)) => {{
         let v = make_closure!($($rest)*);
         let v_type = v.get_type().expect("Internal type error");
-        ValueF::NEOptionalLit(v)
-            .into_value_with_type(v_type)
+        let opt_v_type = Value::from_builtin(Builtin::Optional).app(v_type);
+        ValueF::NEOptionalLit(v).into_value_with_type(opt_v_type)
     }};
     (1 + $($rest:tt)*) => {
         ValueF::PartialExpr(ExprF::BinOp(
-- 
cgit v1.3.1


From f9ec2cdf2803ed92fa404db989b786fc1dfac12e Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 25 Aug 2019 17:07:59 +0200
Subject: Enforce type information almost everywhere

---
 dhall/src/core/value.rs      | 66 ++++++++++++++++++++++++--------------------
 dhall/src/core/valuef.rs     |  3 --
 dhall/src/error/mod.rs       |  1 -
 dhall/src/phase/normalize.rs | 25 ++++++-----------
 dhall/src/phase/typecheck.rs | 21 ++++++--------
 5 files changed, 53 insertions(+), 63 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 7f98826..4a78b05 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -27,13 +27,14 @@ pub(crate) enum Form {
 }
 use Form::{Unevaled, NF, WHNF};
 
-#[derive(Debug)]
 /// Partially normalized value.
 /// Invariant: if `form` is `WHNF`, `value` must be in Weak Head Normal Form
 /// Invariant: if `form` is `NF`, `value` must be fully normalized
+#[derive(Debug)]
 struct ValueInternal {
     form: Form,
     value: ValueF,
+    /// This is None if and only if `value` is `Sort` (which doesn't have a type)
     ty: Option<Value>,
 }
 
@@ -69,11 +70,15 @@ impl ValueInternal {
                 value: ValueF::Const(Const::Type),
                 ty: None,
             },
-            |vint| match &vint.form {
-                Unevaled => {
+            |vint| match (&vint.form, &vint.ty) {
+                (Unevaled, None) => ValueInternal {
+                    form: NF,
+                    value: ValueF::Const(Const::Sort),
+                    ty: None,
+                },
+                (Unevaled, Some(ty)) => {
                     let new_value =
-                        normalize_whnf(vint.value, vint.ty.as_ref())
-                            .into_whnf(vint.ty.as_ref());
+                        normalize_whnf(vint.value, &ty).into_whnf(&ty);
                     ValueInternal {
                         form: WHNF,
                         value: new_value,
@@ -81,7 +86,7 @@ impl ValueInternal {
                     }
                 }
                 // Already in WHNF
-                WHNF | NF => vint,
+                (WHNF, _) | (NF, _) => vint,
             },
         )
     }
@@ -103,10 +108,9 @@ impl ValueInternal {
     fn get_type(&self) -> Result<&Value, TypeError> {
         match &self.ty {
             Some(t) => Ok(t),
-            None => Err(TypeError::new(
-                &TypecheckContext::new(),
-                TypeMessage::Untyped,
-            )),
+            None => {
+                Err(TypeError::new(&TypecheckContext::new(), TypeMessage::Sort))
+            }
         }
     }
 }
@@ -115,9 +119,13 @@ impl Value {
     pub(crate) fn new(value: ValueF, form: Form, ty: Option<Value>) -> Value {
         ValueInternal { form, value, ty }.into_value()
     }
+    // TODO: this is very wrong
     pub(crate) fn from_valuef_untyped(v: ValueF) -> Value {
         Value::new(v, Unevaled, None)
     }
+    pub(crate) fn const_sort() -> Value {
+        Value::new(ValueF::Const(Const::Sort), NF, None)
+    }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Value) -> Value {
         Value::new(v, Unevaled, Some(t))
     }
@@ -225,27 +233,30 @@ impl Value {
     }
 
     pub(crate) fn app(&self, v: Value) -> Value {
-        let ty = self.get_type().ok();
-        let vovf = apply_any(self.clone(), v.clone(), ty.as_ref());
-        match self.as_internal().get_type() {
-            Err(_) => vovf.into_value_untyped(),
-            Ok(t) => match &*t.as_whnf() {
-                ValueF::Pi(x, _, e) => {
-                    let t = e.subst_shift(&x.into(), &v);
-                    vovf.into_value_with_type(t)
-                }
-                _ => unreachable!("Internal type error"),
-            },
+        let t = self.get_type_not_sort();
+        let vovf = apply_any(self.clone(), v.clone(), &t);
+        let t_borrow = t.as_whnf();
+        match &*t_borrow {
+            ValueF::Pi(x, _, e) => {
+                let t = e.subst_shift(&x.into(), &v);
+                vovf.into_value_with_type(t)
+            }
+            _ => unreachable!("Internal type error"),
         }
     }
 
     pub(crate) fn get_type(&self) -> Result<Value, TypeError> {
         Ok(self.as_internal().get_type()?.clone())
     }
+    /// When we know the value isn't `Sort`, this gets the type directly
+    pub(crate) fn get_type_not_sort(&self) -> Value {
+        self.get_type()
+            .expect("Internal type error: value is `Sort` but shouldn't be")
+    }
 }
 
 impl VoVF {
-    pub(crate) fn into_whnf(self, ty: Option<&Value>) -> ValueF {
+    pub(crate) fn into_whnf(self, ty: &Value) -> ValueF {
         match self {
             VoVF::ValueF {
                 val,
@@ -256,7 +267,7 @@ impl VoVF {
             VoVF::Value(v) => {
                 let v_ty = v.get_type().ok();
                 debug_assert_eq!(
-                    ty,
+                    Some(ty),
                     v_ty.as_ref(),
                     "The type recovered from normalization doesn't match the stored type."
                 );
@@ -264,12 +275,6 @@ impl VoVF {
             }
         }
     }
-    pub(crate) fn into_value_untyped(self) -> Value {
-        match self {
-            VoVF::Value(v) => v,
-            VoVF::ValueF { val, form } => Value::new(val, form, None),
-        }
-    }
     pub(crate) fn into_value_with_type(self, ty: Value) -> Value {
         match self {
             VoVF::Value(v) => {
@@ -288,7 +293,8 @@ impl VoVF {
     pub(crate) fn app(self, x: Value) -> VoVF {
         VoVF::Value(match self {
             VoVF::Value(v) => v.app(x),
-            VoVF::ValueF { val, .. } => val.into_value_untyped().app(x),
+            // TODO: this is very wrong
+            VoVF::ValueF { val, .. } => Value::from_valuef_untyped(val).app(x),
         })
     }
 }
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 42606a9..5638078 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -47,9 +47,6 @@ pub(crate) enum ValueF {
 }
 
 impl ValueF {
-    pub(crate) fn into_value_untyped(self) -> Value {
-        Value::from_valuef_untyped(self)
-    }
     pub(crate) fn into_value_with_type(self, t: Value) -> Value {
         Value::from_valuef_and_type(self, t)
     }
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 13a9d7e..2ddaf3d 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -54,7 +54,6 @@ pub(crate) enum TypeMessage {
     NotAFunction(Value),
     TypeMismatch(Value, Value, Value),
     AnnotMismatch(Value, Value),
-    Untyped,
     InvalidListElement(usize, Value, Value),
     InvalidListType(Value),
     InvalidOptionalType(Value),
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index fe99696..9837a8b 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -46,7 +46,7 @@ macro_rules! make_closure {
         let var: AlphaLabel = Label::from(stringify!($var)).into();
         let ty = make_closure!($($ty)*);
         let body = make_closure!($($body)*);
-        let body_ty = body.get_type().expect("Internal type error");
+        let body_ty = body.get_type_not_sort();
         let lam_ty = ValueF::Pi(var.clone(), ty.clone(), body_ty)
             .into_value_with_type(Value::from_const(Type));
         ValueF::Lam(var, ty, body).into_value_with_type(lam_ty)
@@ -60,7 +60,7 @@ macro_rules! make_closure {
     };
     (Some($($rest:tt)*)) => {{
         let v = make_closure!($($rest)*);
-        let v_type = v.get_type().expect("Internal type error");
+        let v_type = v.get_type_not_sort();
         let opt_v_type = Value::from_builtin(Builtin::Optional).app(v_type);
         ValueF::NEOptionalLit(v).into_value_with_type(opt_v_type)
     }};
@@ -79,7 +79,7 @@ macro_rules! make_closure {
     ([ $($head:tt)* ] # $($tail:tt)*) => {{
         let head = make_closure!($($head)*);
         let tail = make_closure!($($tail)*);
-        let list_type = tail.get_type().expect("Internal type error");
+        let list_type = tail.get_type_not_sort();
         ValueF::PartialExpr(ExprF::BinOp(
             dhall_syntax::BinOp::ListAppend,
             ValueF::NEListLit(vec![head])
@@ -90,11 +90,7 @@ macro_rules! make_closure {
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub(crate) fn apply_builtin(
-    b: Builtin,
-    args: Vec<Value>,
-    _ty: Option<&Value>,
-) -> VoVF {
+pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
     use dhall_syntax::Builtin::*;
     use ValueF::*;
 
@@ -251,9 +247,7 @@ pub(crate) fn apply_builtin(
                     // Extract the type of the list elements
                     let t = match &*l_whnf {
                         EmptyListLit(t) => t.clone(),
-                        NEListLit(xs) => {
-                            xs[0].get_type().expect("Internal type error")
-                        }
+                        NEListLit(xs) => xs[0].get_type_not_sort(),
                         _ => unreachable!(),
                     };
 
@@ -429,7 +423,7 @@ pub(crate) fn apply_builtin(
     }
 }
 
-pub(crate) fn apply_any(f: Value, a: Value, ty: Option<&Value>) -> VoVF {
+pub(crate) fn apply_any(f: Value, a: Value, ty: &Value) -> VoVF {
     let fallback = |f: Value, a: Value| {
         ValueF::PartialExpr(ExprF::App(f, a)).into_vovf_whnf()
     };
@@ -524,7 +518,7 @@ fn apply_binop<'a>(
     o: BinOp,
     x: &'a Value,
     y: &'a Value,
-    ty: Option<&Value>,
+    ty: &Value,
 ) -> Option<Ret<'a>> {
     use BinOp::{
         BoolAnd, BoolEQ, BoolNE, BoolOr, Equivalence, ListAppend, NaturalPlus,
@@ -618,7 +612,6 @@ fn apply_binop<'a>(
             Ret::ValueRef(y)
         }
         (RecursiveRecordMerge, RecordLit(kvs1), RecordLit(kvs2)) => {
-            let ty = ty.expect("Internal type error");
             let ty_borrow = ty.as_whnf();
             let kts = match &*ty_borrow {
                 RecordType(kts) => kts,
@@ -647,7 +640,7 @@ fn apply_binop<'a>(
 
 pub(crate) fn normalize_one_layer(
     expr: ExprF<Value, Normalized>,
-    ty: Option<&Value>,
+    ty: &Value,
 ) -> VoVF {
     use ValueF::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit,
@@ -808,7 +801,7 @@ pub(crate) fn normalize_one_layer(
 }
 
 /// Normalize a ValueF into WHNF
-pub(crate) fn normalize_whnf(v: ValueF, ty: Option<&Value>) -> VoVF {
+pub(crate) fn normalize_whnf(v: ValueF, ty: &Value) -> VoVF {
     match v {
         ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args, ty),
         ValueF::PartialExpr(e) => normalize_one_layer(e, ty),
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index 270191a..ef2018a 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -129,21 +129,16 @@ fn function_check(a: Const, b: Const) -> Const {
     }
 }
 
-fn type_of_const(c: Const) -> Result<Value, TypeError> {
-    match c {
-        Const::Type => Ok(const_to_value(Const::Kind)),
-        Const::Kind => Ok(const_to_value(Const::Sort)),
-        Const::Sort => {
-            Err(TypeError::new(&TypecheckContext::new(), TypeMessage::Sort))
-        }
-    }
-}
-
 pub(crate) fn const_to_value(c: Const) -> Value {
     let v = ValueF::Const(c);
-    match type_of_const(c) {
-        Ok(t) => Value::from_valuef_and_type(v, t),
-        Err(_) => Value::from_valuef_untyped(v),
+    match c {
+        Const::Type => {
+            Value::from_valuef_and_type(v, const_to_value(Const::Kind))
+        }
+        Const::Kind => {
+            Value::from_valuef_and_type(v, const_to_value(Const::Sort))
+        }
+        Const::Sort => Value::const_sort(),
     }
 }
 
-- 
cgit v1.3.1


From bf37fd9da3782134ca4bca9567c34bbee81784b9 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 25 Aug 2019 21:16:38 +0200
Subject: Rework apply_builtin to enforce preservation of type information

---
 dhall/src/core/value.rs      |  32 ++--
 dhall/src/phase/normalize.rs | 339 ++++++++++++++++++++-----------------------
 tests_buffer                 |   2 +
 3 files changed, 173 insertions(+), 200 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 4a78b05..2554da1 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -116,18 +116,24 @@ impl ValueInternal {
 }
 
 impl Value {
-    pub(crate) fn new(value: ValueF, form: Form, ty: Option<Value>) -> Value {
-        ValueInternal { form, value, ty }.into_value()
-    }
-    // TODO: this is very wrong
-    pub(crate) fn from_valuef_untyped(v: ValueF) -> Value {
-        Value::new(v, Unevaled, None)
+    fn new(value: ValueF, form: Form, ty: Value) -> Value {
+        ValueInternal {
+            form,
+            value,
+            ty: Some(ty),
+        }
+        .into_value()
     }
     pub(crate) fn const_sort() -> Value {
-        Value::new(ValueF::Const(Const::Sort), NF, None)
+        ValueInternal {
+            form: NF,
+            value: ValueF::Const(Const::Sort),
+            ty: None,
+        }
+        .into_value()
     }
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Value) -> Value {
-        Value::new(v, Unevaled, Some(t))
+        Value::new(v, Unevaled, t)
     }
     pub(crate) fn from_const(c: Const) -> Self {
         const_to_value(c)
@@ -286,17 +292,9 @@ impl VoVF {
                 );
                 v
             }
-            VoVF::ValueF { val, form } => Value::new(val, form, Some(ty)),
+            VoVF::ValueF { val, form } => Value::new(val, form, ty),
         }
     }
-
-    pub(crate) fn app(self, x: Value) -> VoVF {
-        VoVF::Value(match self {
-            VoVF::Value(v) => v.app(x),
-            // TODO: this is very wrong
-            VoVF::ValueF { val, .. } => Value::from_valuef_untyped(val).app(x),
-        })
-    }
 }
 
 impl Shift for Value {
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 9837a8b..77f5023 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -11,25 +11,6 @@ use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaLabel, Shift, Subst};
 use crate::phase::Normalized;
 
-// Small helper enum to avoid repetition
-enum Ret<'a> {
-    ValueF(ValueF),
-    Value(Value),
-    ValueRef(&'a Value),
-    Expr(ExprF<Value, Normalized>),
-}
-
-impl<'a> Ret<'a> {
-    fn into_vovf_whnf(self) -> VoVF {
-        match self {
-            Ret::ValueF(v) => v.into_vovf_whnf(),
-            Ret::Value(v) => v.into_vovf(),
-            Ret::ValueRef(v) => v.clone().into_vovf(),
-            Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf_whnf(),
-        }
-    }
-}
-
 // Ad-hoc macro to help construct closures
 macro_rules! make_closure {
     (#$var:ident) => { $var.clone() };
@@ -94,80 +75,77 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
     use dhall_syntax::Builtin::*;
     use ValueF::*;
 
-    // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced.
+    // Small helper enum
+    enum Ret<'a> {
+        ValueF(ValueF),
+        Value(Value),
+        // For applications that can return a function, it's important to keep the remaining
+        // arguments to apply them to the resulting function.
+        ValueWithRemainingArgs(&'a [Value], Value),
+        DoneAsIs,
+    }
+
     let ret = match (b, args.as_slice()) {
-        (OptionalNone, [t, r..]) => {
-            Ok((r, Ret::ValueF(EmptyOptionalLit(t.clone()))))
-        }
-        (NaturalIsZero, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, Ret::ValueF(BoolLit(*n == 0)))),
-            _ => Err(()),
+        (OptionalNone, [t]) => Ret::ValueF(EmptyOptionalLit(t.clone())),
+        (NaturalIsZero, [n]) => match &*n.as_whnf() {
+            NaturalLit(n) => Ret::ValueF(BoolLit(*n == 0)),
+            _ => Ret::DoneAsIs,
         },
-        (NaturalEven, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, Ret::ValueF(BoolLit(*n % 2 == 0)))),
-            _ => Err(()),
+        (NaturalEven, [n]) => match &*n.as_whnf() {
+            NaturalLit(n) => Ret::ValueF(BoolLit(*n % 2 == 0)),
+            _ => Ret::DoneAsIs,
         },
-        (NaturalOdd, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, Ret::ValueF(BoolLit(*n % 2 != 0)))),
-            _ => Err(()),
+        (NaturalOdd, [n]) => match &*n.as_whnf() {
+            NaturalLit(n) => Ret::ValueF(BoolLit(*n % 2 != 0)),
+            _ => Ret::DoneAsIs,
         },
-        (NaturalToInteger, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((r, Ret::ValueF(IntegerLit(*n as isize)))),
-            _ => Err(()),
+        (NaturalToInteger, [n]) => match &*n.as_whnf() {
+            NaturalLit(n) => Ret::ValueF(IntegerLit(*n as isize)),
+            _ => Ret::DoneAsIs,
         },
-        (NaturalShow, [n, r..]) => match &*n.as_whnf() {
-            NaturalLit(n) => Ok((
-                r,
+        (NaturalShow, [n]) => match &*n.as_whnf() {
+            NaturalLit(n) => {
                 Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(
                     n.to_string(),
-                )])),
-            )),
-            _ => Err(()),
+                )]))
+            }
+            _ => Ret::DoneAsIs,
         },
-        (NaturalSubtract, [a, b, r..]) => {
-            match (&*a.as_whnf(), &*b.as_whnf()) {
-                (NaturalLit(a), NaturalLit(b)) => Ok((
-                    r,
-                    Ret::ValueF(NaturalLit(if b > a { b - a } else { 0 })),
-                )),
-                (NaturalLit(0), _) => Ok((r, Ret::ValueRef(b))),
-                (_, NaturalLit(0)) => Ok((r, Ret::ValueF(NaturalLit(0)))),
-                _ if a == b => Ok((r, Ret::ValueF(NaturalLit(0)))),
-                _ => Err(()),
+        (NaturalSubtract, [a, b]) => match (&*a.as_whnf(), &*b.as_whnf()) {
+            (NaturalLit(a), NaturalLit(b)) => {
+                Ret::ValueF(NaturalLit(if b > a { b - a } else { 0 }))
             }
-        }
-        (IntegerShow, [n, r..]) => match &*n.as_whnf() {
+            (NaturalLit(0), _) => Ret::Value(b.clone()),
+            (_, NaturalLit(0)) => Ret::ValueF(NaturalLit(0)),
+            _ if a == b => Ret::ValueF(NaturalLit(0)),
+            _ => Ret::DoneAsIs,
+        },
+        (IntegerShow, [n]) => match &*n.as_whnf() {
             IntegerLit(n) => {
                 let s = if *n < 0 {
                     n.to_string()
                 } else {
                     format!("+{}", n)
                 };
-                Ok((
-                    r,
-                    Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(
-                        s,
-                    )])),
-                ))
+                Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(s)]))
             }
-            _ => Err(()),
+            _ => Ret::DoneAsIs,
         },
-        (IntegerToDouble, [n, r..]) => match &*n.as_whnf() {
+        (IntegerToDouble, [n]) => match &*n.as_whnf() {
             IntegerLit(n) => {
-                Ok((r, Ret::ValueF(DoubleLit(NaiveDouble::from(*n as f64)))))
+                Ret::ValueF(DoubleLit(NaiveDouble::from(*n as f64)))
             }
-            _ => Err(()),
+            _ => Ret::DoneAsIs,
         },
-        (DoubleShow, [n, r..]) => match &*n.as_whnf() {
-            DoubleLit(n) => Ok((
-                r,
+        (DoubleShow, [n]) => match &*n.as_whnf() {
+            DoubleLit(n) => {
                 Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(
                     n.to_string(),
-                )])),
-            )),
-            _ => Err(()),
+                )]))
+            }
+            _ => Ret::DoneAsIs,
         },
-        (TextShow, [v, r..]) => match &*v.as_whnf() {
+        (TextShow, [v]) => match &*v.as_whnf() {
             TextLit(elts) => {
                 match elts.as_slice() {
                     // Empty string literal.
@@ -176,12 +154,9 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
                         let txt: InterpolatedText<Normalized> =
                             std::iter::empty().collect();
                         let s = txt.to_string();
-                        Ok((
-                            r,
-                            Ret::ValueF(TextLit(vec![
-                                InterpolatedTextContents::Text(s),
-                            ])),
-                        ))
+                        Ret::ValueF(TextLit(vec![
+                            InterpolatedTextContents::Text(s),
+                        ]))
                     }
                     // If there are no interpolations (invariants ensure that when there are no
                     // interpolations, there is a single Text item) in the literal.
@@ -193,54 +168,42 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
                             ))
                             .collect();
                         let s = txt.to_string();
-                        Ok((
-                            r,
-                            Ret::ValueF(TextLit(vec![
-                                InterpolatedTextContents::Text(s),
-                            ])),
-                        ))
+                        Ret::ValueF(TextLit(vec![
+                            InterpolatedTextContents::Text(s),
+                        ]))
                     }
-                    _ => Err(()),
+                    _ => Ret::DoneAsIs,
                 }
             }
-            _ => Err(()),
+            _ => Ret::DoneAsIs,
         },
-        (ListLength, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(_) => Ok((r, Ret::ValueF(NaturalLit(0)))),
-            NEListLit(xs) => Ok((r, Ret::ValueF(NaturalLit(xs.len())))),
-            _ => Err(()),
+        (ListLength, [_, l]) => match &*l.as_whnf() {
+            EmptyListLit(_) => Ret::ValueF(NaturalLit(0)),
+            NEListLit(xs) => Ret::ValueF(NaturalLit(xs.len())),
+            _ => Ret::DoneAsIs,
         },
-        (ListHead, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => {
-                Ok((r, Ret::ValueF(EmptyOptionalLit(n.clone()))))
+        (ListHead, [_, l]) => match &*l.as_whnf() {
+            EmptyListLit(n) => Ret::ValueF(EmptyOptionalLit(n.clone())),
+            NEListLit(xs) => {
+                Ret::ValueF(NEOptionalLit(xs.iter().next().unwrap().clone()))
             }
-            NEListLit(xs) => Ok((
-                r,
-                Ret::ValueF(NEOptionalLit(xs.iter().next().unwrap().clone())),
-            )),
-            _ => Err(()),
+            _ => Ret::DoneAsIs,
         },
-        (ListLast, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => {
-                Ok((r, Ret::ValueF(EmptyOptionalLit(n.clone()))))
-            }
-            NEListLit(xs) => Ok((
-                r,
-                Ret::ValueF(NEOptionalLit(
-                    xs.iter().rev().next().unwrap().clone(),
-                )),
+        (ListLast, [_, l]) => match &*l.as_whnf() {
+            EmptyListLit(n) => Ret::ValueF(EmptyOptionalLit(n.clone())),
+            NEListLit(xs) => Ret::ValueF(NEOptionalLit(
+                xs.iter().rev().next().unwrap().clone(),
             )),
-            _ => Err(()),
+            _ => Ret::DoneAsIs,
         },
-        (ListReverse, [_, l, r..]) => match &*l.as_whnf() {
-            EmptyListLit(n) => Ok((r, Ret::ValueF(EmptyListLit(n.clone())))),
-            NEListLit(xs) => Ok((
-                r,
-                Ret::ValueF(NEListLit(xs.iter().rev().cloned().collect())),
-            )),
-            _ => Err(()),
+        (ListReverse, [_, l]) => match &*l.as_whnf() {
+            EmptyListLit(n) => Ret::ValueF(EmptyListLit(n.clone())),
+            NEListLit(xs) => {
+                Ret::ValueF(NEListLit(xs.iter().rev().cloned().collect()))
+            }
+            _ => Ret::DoneAsIs,
         },
-        (ListIndexed, [_, l, r..]) => {
+        (ListIndexed, [_, l]) => {
             let l_whnf = l.as_whnf();
             match &*l_whnf {
                 EmptyListLit(_) | NEListLit(_) => {
@@ -287,16 +250,16 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
                         ),
                         _ => unreachable!(),
                     };
-                    Ok((r, Ret::ValueF(list)))
+                    Ret::ValueF(list)
                 }
-                _ => Err(()),
+                _ => Ret::DoneAsIs,
             }
         }
-        (ListBuild, [t, f, r..]) => match &*f.as_whnf() {
+        (ListBuild, [t, f]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(ListFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, Ret::Value(args[1].clone())))
+                    Ret::Value(args[1].clone())
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -304,44 +267,41 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
             }
             _ => {
                 let list_t = Value::from_builtin(List).app(t.clone());
-                Ok((
-                    r,
-                    Ret::Value(
-                        f.app(list_t.clone())
-                            .app({
-                                // Move `t` under new variables
-                                let t1 = t.under_binder(Label::from("x"));
-                                let t2 = t1.under_binder(Label::from("xs"));
-                                make_closure!(
-                                    λ(x : #t) ->
-                                    λ(xs : List #t1) ->
-                                    [ var(x, 1, #t2) ] # var(xs, 0, List #t2)
-                                )
-                            })
-                            .app(
-                                EmptyListLit(t.clone())
-                                    .into_value_with_type(list_t),
-                            ),
-                    ),
-                ))
+                Ret::Value(
+                    f.app(list_t.clone())
+                        .app({
+                            // Move `t` under new variables
+                            let t1 = t.under_binder(Label::from("x"));
+                            let t2 = t1.under_binder(Label::from("xs"));
+                            make_closure!(
+                                λ(x : #t) ->
+                                λ(xs : List #t1) ->
+                                [ var(x, 1, #t2) ] # var(xs, 0, List #t2)
+                            )
+                        })
+                        .app(
+                            EmptyListLit(t.clone())
+                                .into_value_with_type(list_t),
+                        ),
+                )
             }
         },
         (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() {
-            EmptyListLit(_) => Ok((r, Ret::ValueRef(nil))),
+            EmptyListLit(_) => Ret::ValueWithRemainingArgs(r, nil.clone()),
             NEListLit(xs) => {
                 let mut v = nil.clone();
                 for x in xs.iter().cloned().rev() {
                     v = cons.app(x).app(v);
                 }
-                Ok((r, Ret::Value(v)))
+                Ret::ValueWithRemainingArgs(r, v)
             }
-            _ => Err(()),
+            _ => Ret::DoneAsIs,
         },
-        (OptionalBuild, [t, f, r..]) => match &*f.as_whnf() {
+        (OptionalBuild, [t, f]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(OptionalFold, args) => {
                 if args.len() >= 2 {
-                    Ok((r, Ret::Value(args[1].clone())))
+                    Ret::Value(args[1].clone())
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
@@ -349,52 +309,51 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
             }
             _ => {
                 let optional_t = Value::from_builtin(Optional).app(t.clone());
-                Ok((
-                    r,
-                    Ret::Value(
-                        f.app(optional_t.clone())
-                            .app({
-                                let t1 = t.under_binder(Label::from("x"));
-                                make_closure!(λ(x: #t) -> Some(var(x, 0, #t1)))
-                            })
-                            .app(
-                                EmptyOptionalLit(t.clone())
-                                    .into_value_with_type(optional_t),
-                            ),
-                    ),
-                ))
+                Ret::Value(
+                    f.app(optional_t.clone())
+                        .app({
+                            let t1 = t.under_binder(Label::from("x"));
+                            make_closure!(λ(x: #t) -> Some(var(x, 0, #t1)))
+                        })
+                        .app(
+                            EmptyOptionalLit(t.clone())
+                                .into_value_with_type(optional_t),
+                        ),
+                )
             }
         },
         (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() {
-            EmptyOptionalLit(_) => Ok((r, Ret::ValueRef(nothing))),
-            NEOptionalLit(x) => Ok((r, Ret::Value(just.app(x.clone())))),
-            _ => Err(()),
+            EmptyOptionalLit(_) => {
+                Ret::ValueWithRemainingArgs(r, nothing.clone())
+            }
+            NEOptionalLit(x) => {
+                Ret::ValueWithRemainingArgs(r, just.app(x.clone()))
+            }
+            _ => Ret::DoneAsIs,
         },
-        (NaturalBuild, [f, r..]) => match &*f.as_whnf() {
+        (NaturalBuild, [f]) => match &*f.as_whnf() {
             // fold/build fusion
             ValueF::AppliedBuiltin(NaturalFold, args) => {
                 if !args.is_empty() {
-                    Ok((r, Ret::Value(args[0].clone())))
+                    Ret::Value(args[0].clone())
                 } else {
                     // Do we really need to handle this case ?
                     unimplemented!()
                 }
             }
-            _ => Ok((
-                r,
-                Ret::Value(
-                    f.app(Value::from_builtin(Natural))
-                        .app(make_closure!(
-                            λ(x : Natural) -> 1 + var(x, 0, Natural)
-                        ))
-                        .app(NaturalLit(0).into_value_with_type(
-                            Value::from_builtin(Natural),
-                        )),
-                ),
-            )),
+            _ => Ret::Value(
+                f.app(Value::from_builtin(Natural))
+                    .app(make_closure!(
+                        λ(x : Natural) -> 1 + var(x, 0, Natural)
+                    ))
+                    .app(
+                        NaturalLit(0)
+                            .into_value_with_type(Value::from_builtin(Natural)),
+                    ),
+            ),
         },
         (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() {
-            NaturalLit(0) => Ok((r, Ret::ValueRef(zero))),
+            NaturalLit(0) => Ret::ValueWithRemainingArgs(r, zero.clone()),
             NaturalLit(n) => {
                 let fold = Value::from_builtin(NaturalFold)
                     .app(
@@ -404,22 +363,23 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
                     .app(t.clone())
                     .app(succ.clone())
                     .app(zero.clone());
-                Ok((r, Ret::Value(succ.app(fold))))
+                Ret::ValueWithRemainingArgs(r, succ.app(fold))
             }
-            _ => Err(()),
+            _ => Ret::DoneAsIs,
         },
-        _ => Err(()),
+        _ => Ret::DoneAsIs,
     };
     match ret {
-        Ok((unconsumed_args, ret)) => {
-            let mut v = ret.into_vovf_whnf();
+        Ret::ValueF(v) => v.into_vovf_whnf(),
+        Ret::Value(v) => v.into_vovf(),
+        Ret::ValueWithRemainingArgs(unconsumed_args, mut v) => {
             let n_consumed_args = args.len() - unconsumed_args.len();
             for x in args.into_iter().skip(n_consumed_args) {
                 v = v.app(x);
             }
-            v
+            v.into_vovf()
         }
-        Err(()) => AppliedBuiltin(b, args).into_vovf_whnf(),
+        Ret::DoneAsIs => AppliedBuiltin(b, args).into_vovf_whnf(),
     }
 }
 
@@ -514,6 +474,14 @@ where
     Ok(kvs)
 }
 
+// Small helper enum to avoid repetition
+enum Ret<'a> {
+    ValueF(ValueF),
+    Value(Value),
+    ValueRef(&'a Value),
+    Expr(ExprF<Value, Normalized>),
+}
+
 fn apply_binop<'a>(
     o: BinOp,
     x: &'a Value,
@@ -797,7 +765,12 @@ pub(crate) fn normalize_one_layer(
         }
     };
 
-    ret.into_vovf_whnf()
+    match ret {
+        Ret::ValueF(v) => v.into_vovf_whnf(),
+        Ret::Value(v) => v.into_vovf(),
+        Ret::ValueRef(v) => v.clone().into_vovf(),
+        Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf_whnf(),
+    }
 }
 
 /// Normalize a ValueF into WHNF
diff --git a/tests_buffer b/tests_buffer
index 93eb626..1ad880e 100644
--- a/tests_buffer
+++ b/tests_buffer
@@ -28,6 +28,8 @@ variables across import boundaries
     TextLitNested1 "${""}${x}"
     TextLitNested2 "${"${x}"}"
     TextLitNested3 "${"${""}"}${x}"
+    regression/
+        NaturalFoldExtraArg Natural/fold 0 (Bool -> Bool) (λ(_ : (Bool -> Bool)) → λ(_ : Bool) → True) (λ(_ : Bool) → False) True
 
 typecheck:
 something that involves destructuring a recordtype after merge
-- 
cgit v1.3.1


From 906cbf5fc4c3bee65f24df1604497e33c6a20833 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 25 Aug 2019 21:52:59 +0200
Subject: Remove now unnecessary VoVF enum

---
 dhall/src/core/value.rs      | 95 +++++++++++++-------------------------------
 dhall/src/core/valuef.rs     | 10 +----
 dhall/src/phase/normalize.rs | 46 +++++++++++----------
 3 files changed, 53 insertions(+), 98 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 2554da1..13f8e59 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -44,15 +44,6 @@ struct ValueInternal {
 #[derive(Clone)]
 pub(crate) struct Value(Rc<RefCell<ValueInternal>>);
 
-/// When a function needs to return either a freshly created ValueF or an existing Value, but
-/// doesn't want to convert both to the same thing, either to avoid unnecessary allocations or to
-/// avoid loss of typ information.
-#[derive(Debug, Clone)]
-pub(crate) enum VoVF {
-    Value(Value),
-    ValueF { val: ValueF, form: Form },
-}
-
 impl ValueInternal {
     fn into_value(self) -> Value {
         Value(Rc::new(RefCell::new(self)))
@@ -76,15 +67,11 @@ impl ValueInternal {
                     value: ValueF::Const(Const::Sort),
                     ty: None,
                 },
-                (Unevaled, Some(ty)) => {
-                    let new_value =
-                        normalize_whnf(vint.value, &ty).into_whnf(&ty);
-                    ValueInternal {
-                        form: WHNF,
-                        value: new_value,
-                        ty: vint.ty,
-                    }
-                }
+                (Unevaled, Some(ty)) => ValueInternal {
+                    form: WHNF,
+                    value: normalize_whnf(vint.value, &ty),
+                    ty: vint.ty,
+                },
                 // Already in WHNF
                 (WHNF, _) | (NF, _) => vint,
             },
@@ -135,6 +122,9 @@ impl Value {
     pub(crate) fn from_valuef_and_type(v: ValueF, t: Value) -> Value {
         Value::new(v, Unevaled, t)
     }
+    pub(crate) fn from_valuef_and_type_whnf(v: ValueF, t: Value) -> Value {
+        Value::new(v, WHNF, t)
+    }
     pub(crate) fn from_const(c: Const) -> Self {
         const_to_value(c)
     }
@@ -182,16 +172,22 @@ impl Value {
     pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
         self.as_whnf().normalize_to_expr_maybe_alpha(true)
     }
-    /// TODO: cloning a valuef can often be avoided
-    pub(crate) fn to_whnf(&self) -> ValueF {
+    pub(crate) fn to_whnf_ignore_type(&self) -> ValueF {
         self.as_whnf().clone()
     }
+    /// Before discarding type information, check that it matches the expected return type.
+    pub(crate) fn to_whnf_check_type(&self, ty: &Value) -> ValueF {
+        let self_ty = self.get_type().ok();
+        debug_assert_eq!(
+            Some(ty),
+            self_ty.as_ref(),
+            "The value returned from normalization doesn't have the expected type."
+        );
+        self.to_whnf_ignore_type()
+    }
     pub(crate) fn into_typed(self) -> Typed {
         Typed::from_value(self)
     }
-    pub(crate) fn into_vovf(self) -> VoVF {
-        VoVF::Value(self)
-    }
 
     /// Mutates the contents. If no one else shares this, this avoids a RefCell lock.
     fn mutate_internal(&mut self, f: impl FnOnce(&mut ValueInternal)) {
@@ -239,16 +235,14 @@ impl Value {
     }
 
     pub(crate) fn app(&self, v: Value) -> Value {
-        let t = self.get_type_not_sort();
-        let vovf = apply_any(self.clone(), v.clone(), &t);
-        let t_borrow = t.as_whnf();
-        match &*t_borrow {
-            ValueF::Pi(x, _, e) => {
-                let t = e.subst_shift(&x.into(), &v);
-                vovf.into_value_with_type(t)
-            }
+        let body_t = match &*self.get_type_not_sort().as_whnf() {
+            ValueF::Pi(x, _, e) => e.subst_shift(&x.into(), &v),
             _ => unreachable!("Internal type error"),
-        }
+        };
+        Value::from_valuef_and_type_whnf(
+            apply_any(self.clone(), v, &body_t),
+            body_t,
+        )
     }
 
     pub(crate) fn get_type(&self) -> Result<Value, TypeError> {
@@ -261,42 +255,6 @@ impl Value {
     }
 }
 
-impl VoVF {
-    pub(crate) fn into_whnf(self, ty: &Value) -> ValueF {
-        match self {
-            VoVF::ValueF {
-                val,
-                form: Unevaled,
-            } => normalize_whnf(val, ty).into_whnf(ty),
-            // Already at lest in WHNF
-            VoVF::ValueF { val, .. } => val,
-            VoVF::Value(v) => {
-                let v_ty = v.get_type().ok();
-                debug_assert_eq!(
-                    Some(ty),
-                    v_ty.as_ref(),
-                    "The type recovered from normalization doesn't match the stored type."
-                );
-                v.to_whnf()
-            }
-        }
-    }
-    pub(crate) fn into_value_with_type(self, ty: Value) -> Value {
-        match self {
-            VoVF::Value(v) => {
-                let v_ty = v.get_type().ok();
-                debug_assert_eq!(
-                    Some(&ty),
-                    v_ty.as_ref(),
-                    "The type recovered from normalization doesn't match the stored type."
-                );
-                v
-            }
-            VoVF::ValueF { val, form } => Value::new(val, form, ty),
-        }
-    }
-}
-
 impl Shift for Value {
     fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
         Some(Value(self.0.shift(delta, var)?))
@@ -324,6 +282,7 @@ impl Subst<Value> for ValueInternal {
         ValueInternal {
             // The resulting value may not stay in wnhf after substitution
             form: Unevaled,
+            // TODO: check type info if self.value if Var(v) and v == var
             value: self.value.subst_shift(var, val),
             ty: self.ty.subst_shift(var, val),
         }
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 5638078..9ea2467 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble, Natural,
 };
 
-use crate::core::value::{Form, Value, VoVF};
+use crate::core::value::Value;
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::{Normalized, NormalizedSubExpr};
 
@@ -50,12 +50,6 @@ impl ValueF {
     pub(crate) fn into_value_with_type(self, t: Value) -> Value {
         Value::from_valuef_and_type(self, t)
     }
-    pub(crate) fn into_vovf_whnf(self) -> VoVF {
-        VoVF::ValueF {
-            val: self,
-            form: Form::WHNF,
-        }
-    }
 
     /// Convert the value to a fully normalized syntactic expression
     pub(crate) fn normalize_to_expr(&self) -> NormalizedSubExpr {
@@ -339,7 +333,7 @@ impl Subst<Value> for ValueF {
                 t.subst_shift(var, val),
                 e.subst_shift(&var.under_binder(x), &val.under_binder(x)),
             ),
-            ValueF::Var(v) if v == var => val.to_whnf(),
+            ValueF::Var(v) if v == var => val.to_whnf_ignore_type(),
             ValueF::Var(v) => ValueF::Var(v.shift(-1, var).unwrap()),
             ValueF::Const(c) => ValueF::Const(*c),
             ValueF::BoolLit(b) => ValueF::BoolLit(*b),
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 77f5023..82a378c 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -6,7 +6,7 @@ use dhall_syntax::{
     NaiveDouble,
 };
 
-use crate::core::value::{Value, VoVF};
+use crate::core::value::Value;
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaLabel, Shift, Subst};
 use crate::phase::Normalized;
@@ -71,7 +71,11 @@ macro_rules! make_closure {
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
+pub(crate) fn apply_builtin(
+    b: Builtin,
+    args: Vec<Value>,
+    ty: &Value,
+) -> ValueF {
     use dhall_syntax::Builtin::*;
     use ValueF::*;
 
@@ -370,38 +374,36 @@ pub(crate) fn apply_builtin(b: Builtin, args: Vec<Value>, _ty: &Value) -> VoVF {
         _ => Ret::DoneAsIs,
     };
     match ret {
-        Ret::ValueF(v) => v.into_vovf_whnf(),
-        Ret::Value(v) => v.into_vovf(),
+        Ret::ValueF(v) => v,
+        Ret::Value(v) => v.to_whnf_check_type(ty),
         Ret::ValueWithRemainingArgs(unconsumed_args, mut v) => {
             let n_consumed_args = args.len() - unconsumed_args.len();
             for x in args.into_iter().skip(n_consumed_args) {
                 v = v.app(x);
             }
-            v.into_vovf()
+            v.to_whnf_check_type(ty)
         }
-        Ret::DoneAsIs => AppliedBuiltin(b, args).into_vovf_whnf(),
+        Ret::DoneAsIs => AppliedBuiltin(b, args),
     }
 }
 
-pub(crate) fn apply_any(f: Value, a: Value, ty: &Value) -> VoVF {
-    let fallback = |f: Value, a: Value| {
-        ValueF::PartialExpr(ExprF::App(f, a)).into_vovf_whnf()
-    };
-
+pub(crate) fn apply_any(f: Value, a: Value, ty: &Value) -> ValueF {
     let f_borrow = f.as_whnf();
     match &*f_borrow {
-        ValueF::Lam(x, _, e) => e.subst_shift(&x.into(), &a).into_vovf(),
+        ValueF::Lam(x, _, e) => {
+            e.subst_shift(&x.into(), &a).to_whnf_check_type(ty)
+        }
         ValueF::AppliedBuiltin(b, args) => {
             use std::iter::once;
             let args = args.iter().cloned().chain(once(a.clone())).collect();
             apply_builtin(*b, args, ty)
         }
         ValueF::UnionConstructor(l, kts) => {
-            ValueF::UnionLit(l.clone(), a, kts.clone()).into_vovf_whnf()
+            ValueF::UnionLit(l.clone(), a, kts.clone())
         }
         _ => {
             drop(f_borrow);
-            fallback(f, a)
+            ValueF::PartialExpr(ExprF::App(f, a))
         }
     }
 }
@@ -609,7 +611,7 @@ fn apply_binop<'a>(
 pub(crate) fn normalize_one_layer(
     expr: ExprF<Value, Normalized>,
     ty: &Value,
-) -> VoVF {
+) -> ValueF {
     use ValueF::{
         AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit,
         NEListLit, NEOptionalLit, NaturalLit, RecordLit, TextLit,
@@ -766,22 +768,22 @@ pub(crate) fn normalize_one_layer(
     };
 
     match ret {
-        Ret::ValueF(v) => v.into_vovf_whnf(),
-        Ret::Value(v) => v.into_vovf(),
-        Ret::ValueRef(v) => v.clone().into_vovf(),
-        Ret::Expr(expr) => ValueF::PartialExpr(expr).into_vovf_whnf(),
+        Ret::ValueF(v) => v,
+        Ret::Value(v) => v.to_whnf_check_type(ty),
+        Ret::ValueRef(v) => v.to_whnf_check_type(ty),
+        Ret::Expr(expr) => ValueF::PartialExpr(expr),
     }
 }
 
 /// Normalize a ValueF into WHNF
-pub(crate) fn normalize_whnf(v: ValueF, ty: &Value) -> VoVF {
+pub(crate) fn normalize_whnf(v: ValueF, ty: &Value) -> ValueF {
     match v {
         ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args, ty),
         ValueF::PartialExpr(e) => normalize_one_layer(e, ty),
         ValueF::TextLit(elts) => {
-            ValueF::TextLit(squash_textlit(elts.into_iter())).into_vovf_whnf()
+            ValueF::TextLit(squash_textlit(elts.into_iter()))
         }
         // All other cases are already in WHNF
-        v => v.into_vovf_whnf(),
+        v => v,
     }
 }
-- 
cgit v1.3.1


From 829fff5bd3e2115c0a16d40a4dc266747d622b08 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 26 Aug 2019 18:54:29 +0200
Subject: Check correctness of type info in a few more places

---
 dhall/src/core/value.rs | 60 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 43 insertions(+), 17 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 13f8e59..21ac288 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -62,16 +62,17 @@ impl ValueInternal {
                 ty: None,
             },
             |vint| match (&vint.form, &vint.ty) {
-                (Unevaled, None) => ValueInternal {
-                    form: NF,
-                    value: ValueF::Const(Const::Sort),
-                    ty: None,
-                },
                 (Unevaled, Some(ty)) => ValueInternal {
                     form: WHNF,
                     value: normalize_whnf(vint.value, &ty),
                     ty: vint.ty,
                 },
+                // `value` is `Sort`
+                (Unevaled, None) => ValueInternal {
+                    form: NF,
+                    value: ValueF::Const(Const::Sort),
+                    ty: None,
+                },
                 // Already in WHNF
                 (WHNF, _) | (NF, _) => vint,
             },
@@ -177,12 +178,7 @@ impl Value {
     }
     /// Before discarding type information, check that it matches the expected return type.
     pub(crate) fn to_whnf_check_type(&self, ty: &Value) -> ValueF {
-        let self_ty = self.get_type().ok();
-        debug_assert_eq!(
-            Some(ty),
-            self_ty.as_ref(),
-            "The value returned from normalization doesn't have the expected type."
-        );
+        self.check_type(ty);
         self.to_whnf_ignore_type()
     }
     pub(crate) fn into_typed(self) -> Typed {
@@ -236,7 +232,10 @@ impl Value {
 
     pub(crate) fn app(&self, v: Value) -> Value {
         let body_t = match &*self.get_type_not_sort().as_whnf() {
-            ValueF::Pi(x, _, e) => e.subst_shift(&x.into(), &v),
+            ValueF::Pi(x, t, e) => {
+                v.check_type(t);
+                e.subst_shift(&x.into(), &v)
+            }
             _ => unreachable!("Internal type error"),
         };
         Value::from_valuef_and_type_whnf(
@@ -245,6 +244,15 @@ impl Value {
         )
     }
 
+    /// In debug mode, panic if the provided type doesn't match the value's type.
+    /// Otherwise does nothing.
+    pub(crate) fn check_type(&self, ty: &Value) {
+        debug_assert_eq!(
+            Some(ty),
+            self.get_type().ok().as_ref(),
+            "Internal type error"
+        );
+    }
     pub(crate) fn get_type(&self) -> Result<Value, TypeError> {
         Ok(self.as_internal().get_type()?.clone())
     }
@@ -273,7 +281,17 @@ impl Shift for ValueInternal {
 
 impl Subst<Value> for Value {
     fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
-        Value(self.0.subst_shift(var, val))
+        match &*self.as_valuef() {
+            // If the var matches, we can just reuse the provided value instead of copying it.
+            // We also check that the types match, if in debug mode.
+            ValueF::Var(v) if v == var => {
+                if let Ok(self_ty) = self.get_type() {
+                    val.check_type(&self_ty.subst_shift(var, val));
+                }
+                val.clone()
+            }
+            _ => Value(self.0.subst_shift(var, val)),
+        }
     }
 }
 
@@ -282,7 +300,6 @@ impl Subst<Value> for ValueInternal {
         ValueInternal {
             // The resulting value may not stay in wnhf after substitution
             form: Unevaled,
-            // TODO: check type info if self.value if Var(v) and v == var
             value: self.value.subst_shift(var, val),
             ty: self.ty.subst_shift(var, val),
         }
@@ -300,8 +317,17 @@ impl std::cmp::Eq for Value {}
 impl std::fmt::Debug for Value {
     fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let vint: &ValueInternal = &self.as_internal();
-        fmt.debug_tuple(&format!("Value@{:?}", &vint.form))
-            .field(&vint.value)
-            .finish()
+        if let ValueF::Const(c) = &vint.value {
+            write!(fmt, "{:?}", c)
+        } else {
+            let mut x = fmt.debug_struct(&format!("Value@{:?}", &vint.form));
+            x.field("value", &vint.value);
+            if let Some(ty) = vint.ty.as_ref() {
+                x.field("type", &ty);
+            } else {
+                x.field("type", &None::<()>);
+            }
+            x.finish()
+        }
     }
 }
-- 
cgit v1.3.1


From a7363042a16364a6dafdd545f4069dcf04a4197e Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 27 Aug 2019 23:18:13 +0200
Subject: Rename SubExpr to Expr, and Expr to RawExpr

For clarity, and consistency with Value
---
 dhall/src/core/value.rs          |  8 ++---
 dhall/src/core/valuef.rs         |  6 ++--
 dhall/src/error/mod.rs           |  8 ++---
 dhall/src/phase/binary.rs        | 49 ++++++++++++++----------------
 dhall/src/phase/mod.rs           | 22 +++++++-------
 dhall/src/phase/resolve.rs       |  4 +--
 dhall/src/phase/typecheck.rs     | 16 +++++-----
 dhall_syntax/src/core/expr.rs    | 64 ++++++++++++++++++++--------------------
 dhall_syntax/src/core/visitor.rs |  9 +++---
 dhall_syntax/src/parser.rs       | 64 ++++++++++++++++++++--------------------
 dhall_syntax/src/printer.rs      |  6 ++--
 serde_dhall/src/lib.rs           |  4 +--
 serde_dhall/src/serde.rs         |  4 +--
 13 files changed, 129 insertions(+), 135 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 21ac288..49e30cd 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -9,7 +9,7 @@ use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{TypeError, TypeMessage};
 use crate::phase::normalize::{apply_any, normalize_whnf};
 use crate::phase::typecheck::{builtin_to_value, const_to_value};
-use crate::phase::{NormalizedSubExpr, Typed};
+use crate::phase::{NormalizedExpr, Typed};
 
 #[derive(Debug, Clone, Copy)]
 pub(crate) enum Form {
@@ -166,11 +166,11 @@ impl Value {
     }
 
     // TODO: rename `normalize_to_expr`
-    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr(&self) -> NormalizedExpr {
         self.as_whnf().normalize_to_expr()
     }
     // TODO: rename `normalize_to_expr_maybe_alpha`
-    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedExpr {
         self.as_whnf().normalize_to_expr_maybe_alpha(true)
     }
     pub(crate) fn to_whnf_ignore_type(&self) -> ValueF {
@@ -226,7 +226,7 @@ impl Value {
     pub(crate) fn normalize_to_expr_maybe_alpha(
         &self,
         alpha: bool,
-    ) -> NormalizedSubExpr {
+    ) -> NormalizedExpr {
         self.as_nf().normalize_to_expr_maybe_alpha(alpha)
     }
 
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 9ea2467..959f299 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -7,7 +7,7 @@ use dhall_syntax::{
 
 use crate::core::value::Value;
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
-use crate::phase::{Normalized, NormalizedSubExpr};
+use crate::phase::{Normalized, NormalizedExpr};
 
 /// A semantic value. Subexpressions are Values, which are partially evaluated expressions that are
 /// normalized on-demand.
@@ -52,7 +52,7 @@ impl ValueF {
     }
 
     /// Convert the value to a fully normalized syntactic expression
-    pub(crate) fn normalize_to_expr(&self) -> NormalizedSubExpr {
+    pub(crate) fn normalize_to_expr(&self) -> NormalizedExpr {
         self.normalize_to_expr_maybe_alpha(false)
     }
     /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
@@ -60,7 +60,7 @@ impl ValueF {
     pub(crate) fn normalize_to_expr_maybe_alpha(
         &self,
         alpha: bool,
-    ) -> NormalizedSubExpr {
+    ) -> NormalizedExpr {
         match self {
             ValueF::Lam(x, t, e) => rc(ExprF::Lam(
                 x.to_label_maybe_alpha(alpha),
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 2ddaf3d..6d4e120 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{BinOp, Import, Label, ParseError, V};
 use crate::core::context::TypecheckContext;
 use crate::core::value::Value;
 use crate::phase::resolve::ImportStack;
-use crate::phase::NormalizedSubExpr;
+use crate::phase::NormalizedExpr;
 
 pub type Result<T> = std::result::Result<T, Error>;
 
@@ -22,9 +22,9 @@ pub enum Error {
 
 #[derive(Debug)]
 pub enum ImportError {
-    Recursive(Import<NormalizedSubExpr>, Box<Error>),
-    UnexpectedImport(Import<NormalizedSubExpr>),
-    ImportCycle(ImportStack, Import<NormalizedSubExpr>),
+    Recursive(Import<NormalizedExpr>, Box<Error>),
+    UnexpectedImport(Import<NormalizedExpr>),
+    ImportCycle(ImportStack, Import<NormalizedExpr>),
 }
 
 #[derive(Debug)]
diff --git a/dhall/src/phase/binary.rs b/dhall/src/phase/binary.rs
index 3746635..7dc9be2 100644
--- a/dhall/src/phase/binary.rs
+++ b/dhall/src/phase/binary.rs
@@ -4,28 +4,26 @@ use std::iter::FromIterator;
 
 use dhall_syntax::map::DupTreeMap;
 use dhall_syntax::{
-    rc, ExprF, FilePrefix, Hash, Import, ImportLocation, ImportMode, Integer,
-    InterpolatedText, Label, Natural, Scheme, SubExpr, URL, V,
+    rc, Expr, ExprF, FilePrefix, Hash, Import, ImportLocation, ImportMode,
+    Integer, InterpolatedText, Label, Natural, Scheme, URL, V,
 };
 
 use crate::error::{DecodeError, EncodeError};
-use crate::phase::DecodedSubExpr;
+use crate::phase::DecodedExpr;
 
-pub(crate) fn decode(data: &[u8]) -> Result<DecodedSubExpr, DecodeError> {
+pub(crate) fn decode(data: &[u8]) -> Result<DecodedExpr, DecodeError> {
     match serde_cbor::de::from_slice(data) {
         Ok(v) => cbor_value_to_dhall(&v),
         Err(e) => Err(DecodeError::CBORError(e)),
     }
 }
 
-pub(crate) fn encode<E>(expr: &SubExpr<E>) -> Result<Vec<u8>, EncodeError> {
+pub(crate) fn encode<E>(expr: &Expr<E>) -> Result<Vec<u8>, EncodeError> {
     serde_cbor::ser::to_vec(&Serialize::Expr(expr))
         .map_err(|e| EncodeError::CBORError(e))
 }
 
-fn cbor_value_to_dhall(
-    data: &cbor::Value,
-) -> Result<DecodedSubExpr, DecodeError> {
+fn cbor_value_to_dhall(data: &cbor::Value) -> Result<DecodedExpr, DecodeError> {
     use cbor::Value::*;
     use dhall_syntax::{BinOp, Builtin, Const};
     use ExprF::*;
@@ -382,7 +380,7 @@ fn cbor_map_to_dhall_map<'a, T>(
     map: impl IntoIterator<Item = (&'a cbor::ObjectKey, &'a cbor::Value)>,
 ) -> Result<T, DecodeError>
 where
-    T: FromIterator<(Label, DecodedSubExpr)>,
+    T: FromIterator<(Label, DecodedExpr)>,
 {
     map.into_iter()
         .map(|(k, v)| -> Result<(_, _), _> {
@@ -399,7 +397,7 @@ fn cbor_map_to_dhall_opt_map<'a, T>(
     map: impl IntoIterator<Item = (&'a cbor::ObjectKey, &'a cbor::Value)>,
 ) -> Result<T, DecodeError>
 where
-    T: FromIterator<(Label, Option<DecodedSubExpr>)>,
+    T: FromIterator<(Label, Option<DecodedExpr>)>,
 {
     map.into_iter()
         .map(|(k, v)| -> Result<(_, _), _> {
@@ -416,10 +414,10 @@ where
 }
 
 enum Serialize<'a, E> {
-    Expr(&'a SubExpr<E>),
+    Expr(&'a Expr<E>),
     CBOR(cbor::Value),
-    RecordMap(&'a DupTreeMap<Label, SubExpr<E>>),
-    UnionMap(&'a DupTreeMap<Label, Option<SubExpr<E>>>),
+    RecordMap(&'a DupTreeMap<Label, Expr<E>>),
+    UnionMap(&'a DupTreeMap<Label, Option<Expr<E>>>),
 }
 
 macro_rules! count {
@@ -439,7 +437,7 @@ macro_rules! ser_seq {
     }};
 }
 
-fn serialize_subexpr<S, E>(ser: S, e: &SubExpr<E>) -> Result<S::Ok, S::Error>
+fn serialize_subexpr<S, E>(ser: S, e: &Expr<E>) -> Result<S::Ok, S::Error>
 where
     S: serde::ser::Serializer,
 {
@@ -449,7 +447,7 @@ where
     use std::iter::once;
 
     use self::Serialize::{RecordMap, UnionMap};
-    fn expr<E>(x: &SubExpr<E>) -> self::Serialize<'_, E> {
+    fn expr<E>(x: &Expr<E>) -> self::Serialize<'_, E> {
         self::Serialize::Expr(x)
     }
     let cbor =
@@ -566,7 +564,7 @@ where
 
 fn serialize_import<S, E>(
     ser: S,
-    import: &Import<SubExpr<E>>,
+    import: &Import<Expr<E>>,
 ) -> Result<S::Ok, S::Error>
 where
     S: serde::ser::Serializer,
@@ -675,12 +673,9 @@ impl<'a, E> serde::ser::Serialize for Serialize<'a, E> {
 }
 
 fn collect_nested_applications<'a, E>(
-    e: &'a SubExpr<E>,
-) -> (&'a SubExpr<E>, Vec<&'a SubExpr<E>>) {
-    fn go<'a, E>(
-        e: &'a SubExpr<E>,
-        vec: &mut Vec<&'a SubExpr<E>>,
-    ) -> &'a SubExpr<E> {
+    e: &'a Expr<E>,
+) -> (&'a Expr<E>, Vec<&'a Expr<E>>) {
+    fn go<'a, E>(e: &'a Expr<E>, vec: &mut Vec<&'a Expr<E>>) -> &'a Expr<E> {
         match e.as_ref() {
             ExprF::App(f, a) => {
                 vec.push(a);
@@ -694,15 +689,15 @@ fn collect_nested_applications<'a, E>(
     (e, vec)
 }
 
-type LetBinding<'a, E> = (&'a Label, &'a Option<SubExpr<E>>, &'a SubExpr<E>);
+type LetBinding<'a, E> = (&'a Label, &'a Option<Expr<E>>, &'a Expr<E>);
 
 fn collect_nested_lets<'a, E>(
-    e: &'a SubExpr<E>,
-) -> (&'a SubExpr<E>, Vec<LetBinding<'a, E>>) {
+    e: &'a Expr<E>,
+) -> (&'a Expr<E>, Vec<LetBinding<'a, E>>) {
     fn go<'a, E>(
-        e: &'a SubExpr<E>,
+        e: &'a Expr<E>,
         vec: &mut Vec<LetBinding<'a, E>>,
-    ) -> &'a SubExpr<E> {
+    ) -> &'a Expr<E> {
         match e.as_ref() {
             ExprF::Let(l, t, v, e) => {
                 vec.push((l, t, v));
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index bd8853a..ecc9213 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -1,7 +1,7 @@
 use std::fmt::Display;
 use std::path::Path;
 
-use dhall_syntax::{Builtin, Const, SubExpr};
+use dhall_syntax::{Builtin, Const, Expr};
 
 use crate::core::value::Value;
 use crate::core::valuef::ValueF;
@@ -16,19 +16,19 @@ pub(crate) mod parse;
 pub(crate) mod resolve;
 pub(crate) mod typecheck;
 
-pub type ParsedSubExpr = SubExpr<!>;
-pub type DecodedSubExpr = SubExpr<!>;
-pub type ResolvedSubExpr = SubExpr<Normalized>;
-pub type NormalizedSubExpr = SubExpr<Normalized>;
+pub type ParsedExpr = Expr<!>;
+pub type DecodedExpr = Expr<!>;
+pub type ResolvedExpr = Expr<Normalized>;
+pub type NormalizedExpr = Expr<Normalized>;
 
 #[derive(Debug, Clone)]
-pub struct Parsed(ParsedSubExpr, ImportRoot);
+pub struct Parsed(ParsedExpr, ImportRoot);
 
 /// An expression where all imports have been resolved
 ///
 /// Invariant: there must be no `Import` nodes or `ImportAlt` operations left.
 #[derive(Debug, Clone)]
-pub struct Resolved(ResolvedSubExpr);
+pub struct Resolved(ResolvedExpr);
 
 /// A typed expression
 #[derive(Debug, Clone)]
@@ -102,10 +102,10 @@ impl Typed {
         Typed::from_const(Const::Type)
     }
 
-    pub fn to_expr(&self) -> NormalizedSubExpr {
+    pub fn to_expr(&self) -> NormalizedExpr {
         self.0.to_expr()
     }
-    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedExpr {
         self.0.to_expr_alpha()
     }
     pub(crate) fn to_value(&self) -> Value {
@@ -162,10 +162,10 @@ impl Normalized {
         crate::phase::binary::encode(&self.to_expr())
     }
 
-    pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr(&self) -> NormalizedExpr {
         self.0.to_expr()
     }
-    pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
+    pub(crate) fn to_expr_alpha(&self) -> NormalizedExpr {
         self.0.to_expr_alpha()
     }
     pub(crate) fn into_typed(self) -> Typed {
diff --git a/dhall/src/phase/resolve.rs b/dhall/src/phase/resolve.rs
index 27ae7a3..b715e72 100644
--- a/dhall/src/phase/resolve.rs
+++ b/dhall/src/phase/resolve.rs
@@ -2,9 +2,9 @@ use std::collections::HashMap;
 use std::path::{Path, PathBuf};
 
 use crate::error::{Error, ImportError};
-use crate::phase::{Normalized, NormalizedSubExpr, Parsed, Resolved};
+use crate::phase::{Normalized, NormalizedExpr, Parsed, Resolved};
 
-type Import = dhall_syntax::Import<NormalizedSubExpr>;
+type Import = dhall_syntax::Import<NormalizedExpr>;
 
 /// A root from which to resolve relative imports.
 #[derive(Debug, Clone, PartialEq, Eq)]
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index ab6d882..52a4e47 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -2,7 +2,7 @@ use std::cmp::max;
 use std::collections::HashMap;
 
 use dhall_syntax::{
-    rc, Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label, SubExpr,
+    rc, Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label,
 };
 
 use crate::core::context::TypecheckContext;
@@ -200,7 +200,7 @@ macro_rules! make_type {
 
 fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
     use dhall_syntax::Builtin::*;
-    match b {
+    rc(match b {
         Bool | Natural | Integer | Double | Text => make_type!(Type),
         List | Optional => make_type!(
             Type -> Type
@@ -280,14 +280,14 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
         OptionalNone => make_type!(
             forall (a: Type) -> Optional a
         ),
-    }
+    })
 }
 
 pub(crate) fn builtin_to_value(b: Builtin) -> Value {
     let ctx = TypecheckContext::new();
     Value::from_valuef_and_type(
         ValueF::from_builtin(b),
-        type_with(&ctx, rc(type_of_builtin(b))).unwrap(),
+        type_with(&ctx, type_of_builtin(b)).unwrap(),
     )
 }
 
@@ -297,7 +297,7 @@ pub(crate) fn builtin_to_value(b: Builtin) -> Value {
 /// normalized as well.
 fn type_with(
     ctx: &TypecheckContext,
-    e: SubExpr<Normalized>,
+    e: Expr<Normalized>,
 ) -> Result<Value, TypeError> {
     use dhall_syntax::ExprF::{Annot, Embed, Lam, Let, Pi, Var};
 
@@ -791,13 +791,13 @@ fn type_last_layer(
 /// `type_of` is the same as `type_with` with an empty context, meaning that the
 /// expression must be closed (i.e. no free variables), otherwise type-checking
 /// will fail.
-pub(crate) fn typecheck(e: SubExpr<Normalized>) -> Result<Value, TypeError> {
+pub(crate) fn typecheck(e: Expr<Normalized>) -> Result<Value, TypeError> {
     type_with(&TypecheckContext::new(), e)
 }
 
 pub(crate) fn typecheck_with(
-    expr: SubExpr<Normalized>,
-    ty: SubExpr<Normalized>,
+    expr: Expr<Normalized>,
+    ty: Expr<Normalized>,
 ) -> Result<Value, TypeError> {
     typecheck(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
 }
diff --git a/dhall_syntax/src/core/expr.rs b/dhall_syntax/src/core/expr.rs
index 32166a6..2d73a64 100644
--- a/dhall_syntax/src/core/expr.rs
+++ b/dhall_syntax/src/core/expr.rs
@@ -166,19 +166,21 @@ pub enum Builtin {
     TextShow,
 }
 
-// Each node carries an annotation. In practice it's either X (no annotation) or a Span.
+// Each node carries an annotation.
 #[derive(Debug, Clone)]
-pub struct SubExpr<Embed>(Box<(Expr<Embed>, Option<Span>)>);
+pub struct Expr<Embed>(Box<(RawExpr<Embed>, Option<Span>)>);
 
-impl<Embed: PartialEq> std::cmp::PartialEq for SubExpr<Embed> {
+pub type RawExpr<Embed> = ExprF<Expr<Embed>, Embed>;
+
+impl<Embed: PartialEq> std::cmp::PartialEq for Expr<Embed> {
     fn eq(&self, other: &Self) -> bool {
         self.0.as_ref().0 == other.0.as_ref().0
     }
 }
 
-impl<Embed: Eq> std::cmp::Eq for SubExpr<Embed> {}
+impl<Embed: Eq> std::cmp::Eq for Expr<Embed> {}
 
-impl<Embed: std::hash::Hash> std::hash::Hash for SubExpr<Embed> {
+impl<Embed: std::hash::Hash> std::hash::Hash for Expr<Embed> {
     fn hash<H>(&self, state: &mut H)
     where
         H: std::hash::Hasher,
@@ -187,8 +189,6 @@ impl<Embed: std::hash::Hash> std::hash::Hash for SubExpr<Embed> {
     }
 }
 
-pub type Expr<Embed> = ExprF<SubExpr<Embed>, Embed>;
-
 /// Syntax tree for expressions
 // Having the recursion out of the enum definition enables writing
 // much more generic code and improves pattern-matching behind
@@ -310,11 +310,11 @@ impl<SE, E> ExprF<SE, E> {
     }
 }
 
-impl<E> Expr<E> {
+impl<E> RawExpr<E> {
     pub fn traverse_resolve<E2, Err>(
         &self,
-        visit_import: impl FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
-    ) -> Result<Expr<E2>, Err> {
+        visit_import: impl FnMut(&Import<Expr<E2>>) -> Result<E2, Err>,
+    ) -> Result<RawExpr<E2>, Err> {
         self.traverse_resolve_with_visitor(&mut visitor::ResolveVisitor(
             visit_import,
         ))
@@ -323,9 +323,9 @@ impl<E> Expr<E> {
     pub(crate) fn traverse_resolve_with_visitor<E2, Err, F1>(
         &self,
         visitor: &mut visitor::ResolveVisitor<F1>,
-    ) -> Result<Expr<E2>, Err>
+    ) -> Result<RawExpr<E2>, Err>
     where
-        F1: FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
+        F1: FnMut(&Import<Expr<E2>>) -> Result<E2, Err>,
     {
         match self {
             ExprF::BinOp(BinOp::ImportAlt, l, r) => l
@@ -343,52 +343,52 @@ impl<E> Expr<E> {
     }
 }
 
-impl<E> SubExpr<E> {
-    pub fn as_ref(&self) -> &Expr<E> {
+impl<E> Expr<E> {
+    pub fn as_ref(&self) -> &RawExpr<E> {
         &self.0.as_ref().0
     }
 
-    pub fn new(x: Expr<E>, n: Span) -> Self {
-        SubExpr(Box::new((x, Some(n))))
+    pub fn new(x: RawExpr<E>, n: Span) -> Self {
+        Expr(Box::new((x, Some(n))))
     }
 
-    pub fn from_expr_no_span(x: Expr<E>) -> Self {
-        SubExpr(Box::new((x, None)))
+    pub fn from_expr_no_span(x: RawExpr<E>) -> Self {
+        Expr(Box::new((x, None)))
     }
 
     pub fn from_builtin(b: Builtin) -> Self {
-        SubExpr::from_expr_no_span(ExprF::Builtin(b))
+        Expr::from_expr_no_span(ExprF::Builtin(b))
     }
 
-    pub fn rewrap<E2>(&self, x: Expr<E2>) -> SubExpr<E2> {
-        SubExpr(Box::new((x, (self.0).1.clone())))
+    pub fn rewrap<E2>(&self, x: RawExpr<E2>) -> Expr<E2> {
+        Expr(Box::new((x, (self.0).1.clone())))
     }
 }
 
-impl<E> SubExpr<E> {
+impl<E> Expr<E> {
     pub fn traverse_resolve<E2, Err>(
         &self,
-        visit_import: impl FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
-    ) -> Result<SubExpr<E2>, Err> {
+        visit_import: impl FnMut(&Import<Expr<E2>>) -> Result<E2, Err>,
+    ) -> Result<Expr<E2>, Err> {
         Ok(self.rewrap(self.as_ref().traverse_resolve(visit_import)?))
     }
 }
 
 // Should probably rename this
-pub fn rc<E>(x: Expr<E>) -> SubExpr<E> {
-    SubExpr::from_expr_no_span(x)
+pub fn rc<E>(x: RawExpr<E>) -> Expr<E> {
+    Expr::from_expr_no_span(x)
 }
 
 pub(crate) fn spanned(
     span: Span,
-    x: crate::parser::ParsedExpr,
-) -> crate::parser::ParsedSubExpr {
-    SubExpr::new(x, span)
+    x: crate::parser::ParsedRawExpr,
+) -> crate::parser::ParsedExpr {
+    Expr::new(x, span)
 }
 pub(crate) fn unspanned(
-    x: crate::parser::ParsedExpr,
-) -> crate::parser::ParsedSubExpr {
-    SubExpr::from_expr_no_span(x)
+    x: crate::parser::ParsedRawExpr,
+) -> crate::parser::ParsedExpr {
+    Expr::from_expr_no_span(x)
 }
 
 /// Add an isize to an usize
diff --git a/dhall_syntax/src/core/visitor.rs b/dhall_syntax/src/core/visitor.rs
index 5a5fcc9..49fff60 100644
--- a/dhall_syntax/src/core/visitor.rs
+++ b/dhall_syntax/src/core/visitor.rs
@@ -247,18 +247,17 @@ where
 
 pub struct ResolveVisitor<F1>(pub F1);
 
-impl<'a, 'b, E, E2, Err, F1>
-    ExprFFallibleVisitor<'a, SubExpr<E>, SubExpr<E2>, E, E2>
+impl<'a, 'b, E, E2, Err, F1> ExprFFallibleVisitor<'a, Expr<E>, Expr<E2>, E, E2>
     for &'b mut ResolveVisitor<F1>
 where
-    F1: FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
+    F1: FnMut(&Import<Expr<E2>>) -> Result<E2, Err>,
 {
     type Error = Err;
 
     fn visit_subexpr(
         &mut self,
-        subexpr: &'a SubExpr<E>,
-    ) -> Result<SubExpr<E2>, Self::Error> {
+        subexpr: &'a Expr<E>,
+    ) -> Result<Expr<E2>, Self::Error> {
         Ok(subexpr.rewrap(
             subexpr
                 .as_ref()
diff --git a/dhall_syntax/src/parser.rs b/dhall_syntax/src/parser.rs
index d631a19..defa79b 100644
--- a/dhall_syntax/src/parser.rs
+++ b/dhall_syntax/src/parser.rs
@@ -18,10 +18,10 @@ use crate::*;
 // their own crate because they are quite general and useful. For now they
 // are here and hopefully you can figure out how they work.
 
+pub(crate) type ParsedRawExpr = RawExpr<!>;
 pub(crate) type ParsedExpr = Expr<!>;
-pub(crate) type ParsedSubExpr = SubExpr<!>;
-type ParsedText = InterpolatedText<ParsedSubExpr>;
-type ParsedTextContents = InterpolatedTextContents<ParsedSubExpr>;
+type ParsedText = InterpolatedText<ParsedExpr>;
+type ParsedTextContents = InterpolatedTextContents<ParsedExpr>;
 
 pub type ParseError = pest::error::Error<Rule>;
 
@@ -551,7 +551,7 @@ make_parser! {
     rule!(escaped_interpolation<&'a str>;
         captured_str!(_) => "${"
     );
-    rule!(interpolation<ParsedSubExpr>; children!(
+    rule!(interpolation<ParsedExpr>; children!(
         [expression(e)] => e
     ));
 
@@ -593,7 +593,7 @@ make_parser! {
         },
     ));
 
-    rule!(builtin<ParsedSubExpr>; span;
+    rule!(builtin<ParsedExpr>; span;
         captured_str!(s) => {
             spanned(span, match crate::Builtin::parse(s) {
                 Some(b) => Builtin(b),
@@ -650,7 +650,7 @@ make_parser! {
         }
     );
 
-    rule!(identifier<ParsedSubExpr>; span; children!(
+    rule!(identifier<ParsedExpr>; span; children!(
         [variable(v)] => {
             spanned(span, Var(v))
         },
@@ -708,7 +708,7 @@ make_parser! {
         _ => unreachable!(),
     });
 
-    rule!(http_raw<URL<ParsedSubExpr>>; children!(
+    rule!(http_raw<URL<ParsedExpr>>; children!(
         [scheme(sch), authority(auth), path(p)] => URL {
             scheme: sch,
             authority: auth,
@@ -729,7 +729,7 @@ make_parser! {
 
     rule!(query<String>; captured_str!(s) => s.to_owned());
 
-    rule!(http<URL<ParsedSubExpr>>; children!(
+    rule!(http<URL<ParsedExpr>>; children!(
         [http_raw(url)] => url,
         [http_raw(url), import_expression(e)] =>
             URL { headers: Some(e), ..url },
@@ -764,7 +764,7 @@ make_parser! {
 
     rule!(missing<()>);
 
-    rule!(import_type<ImportLocation<ParsedSubExpr>>; children!(
+    rule!(import_type<ImportLocation<ParsedExpr>>; children!(
         [missing(_)] => {
             ImportLocation::Missing
         },
@@ -789,7 +789,7 @@ make_parser! {
         Hash::SHA256(hex::decode(hash).unwrap())
     });
 
-    rule!(import_hashed<crate::Import<ParsedSubExpr>>; children!(
+    rule!(import_hashed<crate::Import<ParsedExpr>>; children!(
         [import_type(location)] =>
             crate::Import {mode: ImportMode::Code, location, hash: None },
         [import_type(location), hash(h)] =>
@@ -799,7 +799,7 @@ make_parser! {
     rule!(Text<()>);
     rule!(Location<()>);
 
-    rule!(import<ParsedSubExpr>; span; children!(
+    rule!(import<ParsedExpr>; span; children!(
         [import_hashed(imp)] => {
             spanned(span, Import(crate::Import {
                 mode: ImportMode::Code,
@@ -828,13 +828,13 @@ make_parser! {
     rule!(if_<()>);
     rule!(in_<()>);
 
-    rule!(empty_list_literal<ParsedSubExpr>; span; children!(
+    rule!(empty_list_literal<ParsedExpr>; span; children!(
         [application_expression(e)] => {
             spanned(span, EmptyListLit(e))
         },
     ));
 
-    rule!(expression<ParsedSubExpr>; span; children!(
+    rule!(expression<ParsedExpr>; span; children!(
         [lambda(()), label(l), expression(typ),
                 arrow(()), expression(body)] => {
             spanned(span, Lam(l, typ, body))
@@ -869,7 +869,7 @@ make_parser! {
         },
     ));
 
-    rule!(let_binding<(Label, Option<ParsedSubExpr>, ParsedSubExpr)>;
+    rule!(let_binding<(Label, Option<ParsedExpr>, ParsedExpr)>;
             children!(
         [label(name), expression(annot), expression(expr)] =>
             (name, Some(annot), expr),
@@ -880,7 +880,7 @@ make_parser! {
     rule!(List<()>);
     rule!(Optional<()>);
 
-    rule!(operator_expression<ParsedSubExpr>; prec_climb!(
+    rule!(operator_expression<ParsedExpr>; prec_climb!(
         application_expression,
         {
             use Rule::*;
@@ -936,14 +936,14 @@ make_parser! {
     rule!(Some_<()>);
     rule!(toMap<()>);
 
-    rule!(application_expression<ParsedSubExpr>; children!(
+    rule!(application_expression<ParsedExpr>; children!(
         [first_application_expression(e)] => e,
         [first_application_expression(first), import_expression(rest)..] => {
             rest.fold(first, |acc, e| unspanned(App(acc, e)))
         },
     ));
 
-    rule!(first_application_expression<ParsedSubExpr>; span;
+    rule!(first_application_expression<ParsedExpr>; span;
             children!(
         [Some_(()), import_expression(e)] => {
             spanned(span, SomeLit(e))
@@ -954,13 +954,13 @@ make_parser! {
         [import_expression(e)] => e,
     ));
 
-    rule!(import_expression<ParsedSubExpr>; span;
+    rule!(import_expression<ParsedExpr>; span;
             children!(
         [selector_expression(e)] => e,
         [import(e)] => e,
     ));
 
-    rule!(selector_expression<ParsedSubExpr>; children!(
+    rule!(selector_expression<ParsedExpr>; children!(
         [primitive_expression(e)] => e,
         [primitive_expression(first), selector(rest)..] => {
             rest.fold(first, |acc, e| unspanned(match e {
@@ -980,7 +980,7 @@ make_parser! {
         [label(ls)..] => ls.collect(),
     ));
 
-    rule!(primitive_expression<ParsedSubExpr>; span; children!(
+    rule!(primitive_expression<ParsedExpr>; span; children!(
         [double_literal(n)] => spanned(span, DoubleLit(n)),
         [natural_literal(n)] => spanned(span, NaturalLit(n)),
         [integer_literal(n)] => spanned(span, IntegerLit(n)),
@@ -995,15 +995,15 @@ make_parser! {
         [expression(e)] => e,
     ));
 
-    rule!(empty_record_literal<ParsedSubExpr>; span;
+    rule!(empty_record_literal<ParsedExpr>; span;
         captured_str!(_) => spanned(span, RecordLit(Default::default()))
     );
 
-    rule!(empty_record_type<ParsedSubExpr>; span;
+    rule!(empty_record_type<ParsedExpr>; span;
         captured_str!(_) => spanned(span, RecordType(Default::default()))
     );
 
-    rule!(non_empty_record_type_or_literal<ParsedSubExpr>; span;
+    rule!(non_empty_record_type_or_literal<ParsedExpr>; span;
           children!(
         [label(first_label), non_empty_record_type(rest)] => {
             let (first_expr, mut map) = rest;
@@ -1018,28 +1018,28 @@ make_parser! {
     ));
 
     rule!(non_empty_record_type
-          <(ParsedSubExpr, DupTreeMap<Label, ParsedSubExpr>)>; children!(
+          <(ParsedExpr, DupTreeMap<Label, ParsedExpr>)>; children!(
         [expression(expr), record_type_entry(entries)..] => {
             (expr, entries.collect())
         }
     ));
 
-    rule!(record_type_entry<(Label, ParsedSubExpr)>; children!(
+    rule!(record_type_entry<(Label, ParsedExpr)>; children!(
         [label(name), expression(expr)] => (name, expr)
     ));
 
     rule!(non_empty_record_literal
-          <(ParsedSubExpr, DupTreeMap<Label, ParsedSubExpr>)>; children!(
+          <(ParsedExpr, DupTreeMap<Label, ParsedExpr>)>; children!(
         [expression(expr), record_literal_entry(entries)..] => {
             (expr, entries.collect())
         }
     ));
 
-    rule!(record_literal_entry<(Label, ParsedSubExpr)>; children!(
+    rule!(record_literal_entry<(Label, ParsedExpr)>; children!(
         [label(name), expression(expr)] => (name, expr)
     ));
 
-    rule!(union_type<ParsedSubExpr>; span; children!(
+    rule!(union_type<ParsedExpr>; span; children!(
         [empty_union_type(_)] => {
             spanned(span, UnionType(Default::default()))
         },
@@ -1050,12 +1050,12 @@ make_parser! {
 
     rule!(empty_union_type<()>);
 
-    rule!(union_type_entry<(Label, Option<ParsedSubExpr>)>; children!(
+    rule!(union_type_entry<(Label, Option<ParsedExpr>)>; children!(
         [label(name), expression(expr)] => (name, Some(expr)),
         [label(name)] => (name, None),
     ));
 
-    rule!(non_empty_list_literal<ParsedSubExpr>; span;
+    rule!(non_empty_list_literal<ParsedExpr>; span;
           children!(
         [expression(items)..] => spanned(
             span,
@@ -1063,12 +1063,12 @@ make_parser! {
         )
     ));
 
-    rule!(final_expression<ParsedSubExpr>; children!(
+    rule!(final_expression<ParsedExpr>; children!(
         [expression(e), EOI(_)] => e
     ));
 }
 
-pub fn parse_expr(s: &str) -> ParseResult<ParsedSubExpr> {
+pub fn parse_expr(s: &str) -> ParseResult<ParsedExpr> {
     let mut pairs = DhallParser::parse(Rule::final_expression, s)?;
     let rc_input = s.to_string().into();
     let expr = EntryPoint::final_expression(rc_input, pairs.next().unwrap())?;
diff --git a/dhall_syntax/src/printer.rs b/dhall_syntax/src/printer.rs
index 256ea65..276590e 100644
--- a/dhall_syntax/src/printer.rs
+++ b/dhall_syntax/src/printer.rs
@@ -112,7 +112,7 @@ enum PrintPhase {
 // Wraps an Expr with a phase, so that phase selsction can be done
 // separate from the actual printing
 #[derive(Clone)]
-struct PhasedExpr<'a, A>(&'a SubExpr<A>, PrintPhase);
+struct PhasedExpr<'a, A>(&'a Expr<A>, PrintPhase);
 
 impl<'a, A: Display + Clone> Display for PhasedExpr<'a, A> {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
@@ -126,7 +126,7 @@ impl<'a, A: Display + Clone> PhasedExpr<'a, A> {
     }
 }
 
-impl<A: Display + Clone> Expr<A> {
+impl<A: Display + Clone> RawExpr<A> {
     fn fmt_phase(
         &self,
         f: &mut fmt::Formatter,
@@ -202,7 +202,7 @@ impl<A: Display + Clone> Expr<A> {
     }
 }
 
-impl<A: Display + Clone> Display for SubExpr<A> {
+impl<A: Display + Clone> Display for Expr<A> {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         self.as_ref().fmt_phase(f, PrintPhase::Base)
     }
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index ce3468f..9fce42d 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -124,7 +124,7 @@ pub use value::Value;
 
 // A Dhall value.
 pub mod value {
-    use dhall::phase::{NormalizedSubExpr, Parsed, Typed};
+    use dhall::phase::{NormalizedExpr, Parsed, Typed};
     use dhall_syntax::Builtin;
 
     use super::de::{Error, Result};
@@ -148,7 +148,7 @@ pub mod value {
             };
             Ok(Value(typed))
         }
-        pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
+        pub(crate) fn to_expr(&self) -> NormalizedExpr {
             self.0.to_expr()
         }
         pub(crate) fn as_typed(&self) -> &Typed {
diff --git a/serde_dhall/src/serde.rs b/serde_dhall/src/serde.rs
index 94b7e6c..26708c1 100644
--- a/serde_dhall/src/serde.rs
+++ b/serde_dhall/src/serde.rs
@@ -1,6 +1,6 @@
 use std::borrow::Cow;
 
-use dhall::phase::NormalizedSubExpr;
+use dhall::phase::NormalizedExpr;
 use dhall_syntax::ExprF;
 
 use crate::de::{Deserialize, Error, Result};
@@ -15,7 +15,7 @@ where
     }
 }
 
-struct Deserializer<'a>(Cow<'a, NormalizedSubExpr>);
+struct Deserializer<'a>(Cow<'a, NormalizedExpr>);
 
 impl<'de: 'a, 'a> serde::de::IntoDeserializer<'de, Error> for Deserializer<'a> {
     type Deserializer = Deserializer<'a>;
-- 
cgit v1.3.1


From 55c127e70eb484df486a45b25bcf03479eebda10 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Wed, 28 Aug 2019 13:49:27 +0200
Subject: Cleanup conversion of `Value` to `Expr`

---
 dhall/src/core/value.rs  |  34 +++++++---------
 dhall/src/core/valuef.rs | 103 ++++++++++++++---------------------------------
 dhall/src/phase/mod.rs   |  31 +++++++++-----
 serde_dhall/src/lib.rs   |   2 +-
 4 files changed, 67 insertions(+), 103 deletions(-)

(limited to 'dhall/src/core')

diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs
index 49e30cd..3cccb1d 100644
--- a/dhall/src/core/value.rs
+++ b/dhall/src/core/value.rs
@@ -44,6 +44,15 @@ struct ValueInternal {
 #[derive(Clone)]
 pub(crate) struct Value(Rc<RefCell<ValueInternal>>);
 
+#[derive(Copy, Clone)]
+/// Controls conversion from `Value` to `Expr`
+pub(crate) struct ToExprOptions {
+    /// Whether to convert all variables to `_`
+    pub(crate) alpha: bool,
+    /// Whether to normalize before converting
+    pub(crate) normalize: bool,
+}
+
 impl ValueInternal {
     fn into_value(self) -> Value {
         Value(Rc::new(RefCell::new(self)))
@@ -158,20 +167,12 @@ impl Value {
         self.normalize_whnf();
         self.as_valuef()
     }
-    /// WARNING: drop this ref before normalizing the same value or you will run into BorrowMut
-    /// panics.
-    pub(crate) fn as_nf(&self) -> Ref<ValueF> {
-        self.normalize_nf();
-        self.as_valuef()
-    }
 
-    // TODO: rename `normalize_to_expr`
-    pub(crate) fn to_expr(&self) -> NormalizedExpr {
-        self.as_whnf().normalize_to_expr()
-    }
-    // TODO: rename `normalize_to_expr_maybe_alpha`
-    pub(crate) fn to_expr_alpha(&self) -> NormalizedExpr {
-        self.as_whnf().normalize_to_expr_maybe_alpha(true)
+    pub(crate) fn to_expr(&self, opts: ToExprOptions) -> NormalizedExpr {
+        if opts.normalize {
+            self.normalize_whnf();
+        }
+        self.as_valuef().to_expr(opts)
     }
     pub(crate) fn to_whnf_ignore_type(&self) -> ValueF {
         self.as_whnf().clone()
@@ -223,13 +224,6 @@ impl Value {
         }
     }
 
-    pub(crate) fn normalize_to_expr_maybe_alpha(
-        &self,
-        alpha: bool,
-    ) -> NormalizedExpr {
-        self.as_nf().normalize_to_expr_maybe_alpha(alpha)
-    }
-
     pub(crate) fn app(&self, v: Value) -> Value {
         let body_t = match &*self.get_type_not_sort().as_whnf() {
             ValueF::Pi(x, t, e) => {
diff --git a/dhall/src/core/valuef.rs b/dhall/src/core/valuef.rs
index 959f299..7ecec86 100644
--- a/dhall/src/core/valuef.rs
+++ b/dhall/src/core/valuef.rs
@@ -5,7 +5,7 @@ use dhall_syntax::{
     NaiveDouble, Natural,
 };
 
-use crate::core::value::Value;
+use crate::core::value::{ToExprOptions, Value};
 use crate::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::phase::{Normalized, NormalizedExpr};
 
@@ -51,38 +51,23 @@ impl ValueF {
         Value::from_valuef_and_type(self, t)
     }
 
-    /// Convert the value to a fully normalized syntactic expression
-    pub(crate) fn normalize_to_expr(&self) -> NormalizedExpr {
-        self.normalize_to_expr_maybe_alpha(false)
-    }
-    /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
-    /// if alpha is `true`
-    pub(crate) fn normalize_to_expr_maybe_alpha(
-        &self,
-        alpha: bool,
-    ) -> NormalizedExpr {
+    pub(crate) fn to_expr(&self, opts: ToExprOptions) -> NormalizedExpr {
         match self {
             ValueF::Lam(x, t, e) => rc(ExprF::Lam(
-                x.to_label_maybe_alpha(alpha),
-                t.normalize_to_expr_maybe_alpha(alpha),
-                e.normalize_to_expr_maybe_alpha(alpha),
+                x.to_label_maybe_alpha(opts.alpha),
+                t.to_expr(opts),
+                e.to_expr(opts),
             )),
-            ValueF::AppliedBuiltin(b, args) => {
-                let mut e = rc(ExprF::Builtin(*b));
-                for v in args {
-                    e = rc(ExprF::App(
-                        e,
-                        v.normalize_to_expr_maybe_alpha(alpha),
-                    ));
-                }
-                e
-            }
+            ValueF::AppliedBuiltin(b, args) => args
+                .iter()
+                .map(|v| v.to_expr(opts))
+                .fold(rc(ExprF::Builtin(*b)), |acc, v| rc(ExprF::App(acc, v))),
             ValueF::Pi(x, t, e) => rc(ExprF::Pi(
-                x.to_label_maybe_alpha(alpha),
-                t.normalize_to_expr_maybe_alpha(alpha),
-                e.normalize_to_expr_maybe_alpha(alpha),
+                x.to_label_maybe_alpha(opts.alpha),
+                t.to_expr(opts),
+                e.to_expr(opts),
             )),
-            ValueF::Var(v) => rc(ExprF::Var(v.to_var(alpha))),
+            ValueF::Var(v) => rc(ExprF::Var(v.to_var(opts.alpha))),
             ValueF::Const(c) => rc(ExprF::Const(*c)),
             ValueF::BoolLit(b) => rc(ExprF::BoolLit(*b)),
             ValueF::NaturalLit(n) => rc(ExprF::NaturalLit(*n)),
@@ -90,73 +75,47 @@ impl ValueF {
             ValueF::DoubleLit(n) => rc(ExprF::DoubleLit(*n)),
             ValueF::EmptyOptionalLit(n) => rc(ExprF::App(
                 rc(ExprF::Builtin(Builtin::OptionalNone)),
-                n.normalize_to_expr_maybe_alpha(alpha),
+                n.to_expr(opts),
             )),
-            ValueF::NEOptionalLit(n) => {
-                rc(ExprF::SomeLit(n.normalize_to_expr_maybe_alpha(alpha)))
-            }
+            ValueF::NEOptionalLit(n) => rc(ExprF::SomeLit(n.to_expr(opts))),
             ValueF::EmptyListLit(n) => rc(ExprF::EmptyListLit(rc(ExprF::App(
                 rc(ExprF::Builtin(Builtin::List)),
-                n.normalize_to_expr_maybe_alpha(alpha),
+                n.to_expr(opts),
             )))),
             ValueF::NEListLit(elts) => rc(ExprF::NEListLit(
-                elts.iter()
-                    .map(|n| n.normalize_to_expr_maybe_alpha(alpha))
-                    .collect(),
+                elts.iter().map(|n| n.to_expr(opts)).collect(),
             )),
             ValueF::RecordLit(kvs) => rc(ExprF::RecordLit(
                 kvs.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
-                    })
+                    .map(|(k, v)| (k.clone(), v.to_expr(opts)))
                     .collect(),
             )),
             ValueF::RecordType(kts) => rc(ExprF::RecordType(
                 kts.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
-                    })
+                    .map(|(k, v)| (k.clone(), v.to_expr(opts)))
                     .collect(),
             )),
             ValueF::UnionType(kts) => rc(ExprF::UnionType(
                 kts.iter()
                     .map(|(k, v)| {
-                        (
-                            k.clone(),
-                            v.as_ref().map(|v| {
-                                v.normalize_to_expr_maybe_alpha(alpha)
-                            }),
-                        )
+                        (k.clone(), v.as_ref().map(|v| v.to_expr(opts)))
                     })
                     .collect(),
             )),
-            ValueF::UnionConstructor(l, kts) => {
-                let kts = kts
-                    .iter()
-                    .map(|(k, v)| {
-                        (
-                            k.clone(),
-                            v.as_ref().map(|v| {
-                                v.normalize_to_expr_maybe_alpha(alpha)
-                            }),
-                        )
-                    })
-                    .collect();
-                rc(ExprF::Field(rc(ExprF::UnionType(kts)), l.clone()))
-            }
+            ValueF::UnionConstructor(l, kts) => rc(ExprF::Field(
+                ValueF::UnionType(kts.clone()).to_expr(opts),
+                l.clone(),
+            )),
             ValueF::UnionLit(l, v, kts) => rc(ExprF::App(
-                ValueF::UnionConstructor(l.clone(), kts.clone())
-                    .normalize_to_expr_maybe_alpha(alpha),
-                v.normalize_to_expr_maybe_alpha(alpha),
+                ValueF::UnionConstructor(l.clone(), kts.clone()).to_expr(opts),
+                v.to_expr(opts),
             )),
             ValueF::TextLit(elts) => {
                 use InterpolatedTextContents::{Expr, Text};
                 rc(ExprF::TextLit(
                     elts.iter()
                         .map(|contents| match contents {
-                            Expr(e) => {
-                                Expr(e.normalize_to_expr_maybe_alpha(alpha))
-                            }
+                            Expr(e) => Expr(e.to_expr(opts)),
                             Text(s) => Text(s.clone()),
                         })
                         .collect(),
@@ -164,12 +123,10 @@ impl ValueF {
             }
             ValueF::Equivalence(x, y) => rc(ExprF::BinOp(
                 dhall_syntax::BinOp::Equivalence,
-                x.normalize_to_expr_maybe_alpha(alpha),
-                y.normalize_to_expr_maybe_alpha(alpha),
+                x.to_expr(opts),
+                y.to_expr(opts),
             )),
-            ValueF::PartialExpr(e) => {
-                rc(e.map_ref(|v| v.normalize_to_expr_maybe_alpha(alpha)))
-            }
+            ValueF::PartialExpr(e) => rc(e.map_ref(|v| v.to_expr(opts))),
         }
     }
 
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index ecc9213..2c5505c 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -3,7 +3,7 @@ use std::path::Path;
 
 use dhall_syntax::{Builtin, Const, Expr};
 
-use crate::core::value::Value;
+use crate::core::value::{ToExprOptions, Value};
 use crate::core::valuef::ValueF;
 use crate::core::var::{AlphaVar, Shift, Subst};
 use crate::error::{EncodeError, Error, ImportError, TypeError};
@@ -71,7 +71,8 @@ impl Resolved {
         Ok(typecheck::typecheck(self.0)?.into_typed())
     }
     pub fn typecheck_with(self, ty: &Typed) -> Result<Typed, TypeError> {
-        Ok(typecheck::typecheck_with(self.0, ty.to_expr())?.into_typed())
+        Ok(typecheck::typecheck_with(self.0, ty.normalize_to_expr())?
+            .into_typed())
     }
 }
 
@@ -102,11 +103,23 @@ impl Typed {
         Typed::from_const(Const::Type)
     }
 
-    pub fn to_expr(&self) -> NormalizedExpr {
-        self.0.to_expr()
-    }
-    pub(crate) fn to_expr_alpha(&self) -> NormalizedExpr {
-        self.0.to_expr_alpha()
+    pub(crate) fn to_expr(&self) -> NormalizedExpr {
+        self.0.to_expr(ToExprOptions {
+            alpha: false,
+            normalize: false,
+        })
+    }
+    pub fn normalize_to_expr(&self) -> NormalizedExpr {
+        self.0.to_expr(ToExprOptions {
+            alpha: false,
+            normalize: true,
+        })
+    }
+    pub(crate) fn normalize_to_expr_alpha(&self) -> NormalizedExpr {
+        self.0.to_expr(ToExprOptions {
+            alpha: true,
+            normalize: true,
+        })
     }
     pub(crate) fn to_value(&self) -> Value {
         self.0.clone()
@@ -163,10 +176,10 @@ impl Normalized {
     }
 
     pub(crate) fn to_expr(&self) -> NormalizedExpr {
-        self.0.to_expr()
+        self.0.normalize_to_expr()
     }
     pub(crate) fn to_expr_alpha(&self) -> NormalizedExpr {
-        self.0.to_expr_alpha()
+        self.0.normalize_to_expr_alpha()
     }
     pub(crate) fn into_typed(self) -> Typed {
         self.0
diff --git a/serde_dhall/src/lib.rs b/serde_dhall/src/lib.rs
index 9fce42d..3d07539 100644
--- a/serde_dhall/src/lib.rs
+++ b/serde_dhall/src/lib.rs
@@ -149,7 +149,7 @@ pub mod value {
             Ok(Value(typed))
         }
         pub(crate) fn to_expr(&self) -> NormalizedExpr {
-            self.0.to_expr()
+            self.0.normalize_to_expr()
         }
         pub(crate) fn as_typed(&self) -> &Typed {
             &self.0
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