From 423fdeebe9247b16744fae4b50df415bbd08be04 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 6 May 2019 22:09:55 +0200
Subject: Reorganize dhall into a phase structure

---
 dhall/src/phase/normalize.rs | 1888 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1888 insertions(+)
 create mode 100644 dhall/src/phase/normalize.rs

(limited to 'dhall/src/phase/normalize.rs')

diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
new file mode 100644
index 0000000..2340bbd
--- /dev/null
+++ b/dhall/src/phase/normalize.rs
@@ -0,0 +1,1888 @@
+#![allow(non_snake_case)]
+use std::collections::BTreeMap;
+use std::rc::Rc;
+
+use dhall_proc_macros as dhall;
+use dhall_syntax::context::Context;
+use dhall_syntax::{
+    rc, BinOp, Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label,
+    Natural, V, X,
+};
+
+use crate::phase::{NormalizedSubExpr, ResolvedSubExpr, Type, Typed};
+
+type InputSubExpr = ResolvedSubExpr;
+type OutputSubExpr = NormalizedSubExpr;
+
+/// Stores a pair of variables: a normal one and if relevant one
+/// that corresponds to the alpha-normalized version of the first one.
+#[derive(Debug, Clone, Eq)]
+pub(crate) struct AlphaVar {
+    normal: V<Label>,
+    alpha: Option<V<()>>,
+}
+
+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(),
+        }
+    }
+    pub(crate) fn from_var(normal: V<Label>) -> Self {
+        AlphaVar {
+            normal,
+            alpha: None,
+        }
+    }
+    pub(crate) fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
+        AlphaVar {
+            normal: self.normal.shift(delta, &var.normal),
+            alpha: match (&self.alpha, &var.alpha) {
+                (Some(x), Some(v)) => Some(x.shift(delta, v)),
+                _ => None,
+            },
+        }
+    }
+}
+
+/// Equality is 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,
+        }
+    }
+}
+
+impl From<Label> for AlphaVar {
+    fn from(x: Label) -> AlphaVar {
+        AlphaVar {
+            normal: V(x, 0),
+            alpha: Some(V((), 0)),
+        }
+    }
+}
+impl<'a> From<&'a Label> for AlphaVar {
+    fn from(x: &'a Label) -> AlphaVar {
+        x.clone().into()
+    }
+}
+impl From<AlphaLabel> for AlphaVar {
+    fn from(x: AlphaLabel) -> AlphaVar {
+        let l: Label = x.into();
+        l.into()
+    }
+}
+impl<'a> From<&'a AlphaLabel> for AlphaVar {
+    fn from(x: &'a AlphaLabel) -> AlphaVar {
+        x.clone().into()
+    }
+}
+
+// Exactly like a Label, but equality returns always true.
+// This is so that Value equality is exactly alpha-equivalence.
+#[derive(Debug, Clone, Eq)]
+pub(crate) struct AlphaLabel(Label);
+
+impl AlphaLabel {
+    fn to_label_maybe_alpha(&self, alpha: bool) -> Label {
+        if alpha {
+            "_".into()
+        } else {
+            self.to_label()
+        }
+    }
+    fn to_label(&self) -> Label {
+        self.clone().into()
+    }
+}
+
+impl std::cmp::PartialEq for AlphaLabel {
+    fn eq(&self, _other: &Self) -> bool {
+        true
+    }
+}
+
+impl From<Label> for AlphaLabel {
+    fn from(x: Label) -> AlphaLabel {
+        AlphaLabel(x)
+    }
+}
+impl From<AlphaLabel> for Label {
+    fn from(x: AlphaLabel) -> Label {
+        x.0
+    }
+}
+
+#[derive(Debug, Clone)]
+enum EnvItem {
+    Thunk(Thunk),
+    Skip(AlphaVar),
+}
+
+impl EnvItem {
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
+        use EnvItem::*;
+        match self {
+            Thunk(e) => Thunk(e.shift(delta, var)),
+            Skip(v) => Skip(v.shift(delta, var)),
+        }
+    }
+
+    pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        match self {
+            EnvItem::Thunk(e) => EnvItem::Thunk(e.subst_shift(var, val)),
+            EnvItem::Skip(v) if v == var => EnvItem::Thunk(val.to_thunk()),
+            EnvItem::Skip(v) => EnvItem::Skip(v.shift(-1, var)),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub(crate) struct NormalizationContext(Rc<Context<Label, EnvItem>>);
+
+impl NormalizationContext {
+    pub(crate) fn new() -> Self {
+        NormalizationContext(Rc::new(Context::new()))
+    }
+    fn skip(&self, x: &Label) -> Self {
+        NormalizationContext(Rc::new(
+            self.0
+                .map(|_, e| e.shift(1, &x.into()))
+                .insert(x.clone(), EnvItem::Skip(x.into())),
+        ))
+    }
+    fn lookup(&self, var: &V<Label>) -> Value {
+        let V(x, n) = var;
+        match self.0.lookup(x, *n) {
+            Some(EnvItem::Thunk(t)) => t.to_value(),
+            Some(EnvItem::Skip(newvar)) => Value::Var(newvar.clone()),
+            // Free variable
+            None => Value::Var(AlphaVar::from_var(var.clone())),
+        }
+    }
+    pub(crate) fn from_typecheck_ctx(
+        tc_ctx: &crate::phase::typecheck::TypecheckContext,
+    ) -> Self {
+        use crate::phase::typecheck::EnvItem::*;
+        let mut ctx = Context::new();
+        for (k, vs) in tc_ctx.0.iter_keys() {
+            for v in vs.iter() {
+                let new_item = match v {
+                    Type(var, _) => EnvItem::Skip(var.clone()),
+                    Value(e) => EnvItem::Thunk(e.to_thunk()),
+                };
+                ctx = ctx.insert(k.clone(), new_item);
+            }
+        }
+        NormalizationContext(Rc::new(ctx))
+    }
+
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
+        NormalizationContext(Rc::new(self.0.map(|_, e| e.shift(delta, var))))
+    }
+
+    fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        NormalizationContext(Rc::new(
+            self.0.map(|_, e| e.subst_shift(var, val)),
+        ))
+    }
+}
+
+/// A semantic value.
+/// Equality is up to alpha-equivalence (renaming of bound variables).
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) enum Value {
+    /// Closures
+    Lam(AlphaLabel, Thunk, Thunk),
+    AppliedBuiltin(Builtin, Vec<Thunk>),
+    /// `λ(x: a) -> Some x`
+    OptionalSomeClosure(TypeThunk),
+    /// `λ(x : a) -> λ(xs : List a) -> [ x ] # xs`
+    /// `λ(xs : List a) -> [ x ] # xs`
+    ListConsClosure(TypeThunk, Option<Thunk>),
+    /// `λ(x : Natural) -> x + 1`
+    NaturalSuccClosure,
+    Pi(AlphaLabel, TypeThunk, TypeThunk),
+
+    Var(AlphaVar),
+    Const(Const),
+    BoolLit(bool),
+    NaturalLit(Natural),
+    IntegerLit(Integer),
+    EmptyOptionalLit(TypeThunk),
+    NEOptionalLit(Thunk),
+    EmptyListLit(TypeThunk),
+    NEListLit(Vec<Thunk>),
+    RecordLit(BTreeMap<Label, Thunk>),
+    RecordType(BTreeMap<Label, TypeThunk>),
+    UnionType(BTreeMap<Label, Option<TypeThunk>>),
+    UnionConstructor(Label, BTreeMap<Label, Option<TypeThunk>>),
+    UnionLit(Label, Thunk, BTreeMap<Label, Option<TypeThunk>>),
+    TextLit(Vec<InterpolatedTextContents<Thunk>>),
+    /// Invariant: This must not contain a value captured by one of the variants above.
+    PartialExpr(ExprF<Thunk, Label, X>),
+}
+
+impl Value {
+    pub(crate) fn into_thunk(self) -> Thunk {
+        Thunk::from_value(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 {
+            Value::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) => {
+                let mut e = rc(ExprF::Builtin(*b));
+                for v in args {
+                    e = rc(ExprF::App(
+                        e,
+                        v.normalize_to_expr_maybe_alpha(alpha),
+                    ));
+                }
+                e
+            }
+            Value::OptionalSomeClosure(n) => {
+                let a = n.normalize_to_expr_maybe_alpha(alpha);
+                dhall::subexpr!(λ(x: a) -> Some x)
+            }
+            Value::ListConsClosure(a, None) => {
+                // Avoid accidental capture of the new `x` variable
+                let a1 = a.shift(1, &Label::from("x").into());
+                let a1 = a1.normalize_to_expr_maybe_alpha(alpha);
+                let a = a.normalize_to_expr_maybe_alpha(alpha);
+                dhall::subexpr!(λ(x : a) -> λ(xs : List a1) -> [ x ] # xs)
+            }
+            Value::ListConsClosure(n, Some(v)) => {
+                // Avoid accidental capture of the new `xs` variable
+                let v = v.shift(1, &Label::from("xs").into());
+                let v = v.normalize_to_expr_maybe_alpha(alpha);
+                let a = n.normalize_to_expr_maybe_alpha(alpha);
+                dhall::subexpr!(λ(xs : List a) -> [ v ] # xs)
+            }
+            Value::NaturalSuccClosure => {
+                dhall::subexpr!(λ(x : Natural) -> x + 1)
+            }
+            Value::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::EmptyOptionalLit(n) => rc(ExprF::App(
+                rc(ExprF::Builtin(Builtin::OptionalNone)),
+                n.normalize_to_expr_maybe_alpha(alpha),
+            )),
+            Value::NEOptionalLit(n) => {
+                rc(ExprF::SomeLit(n.normalize_to_expr_maybe_alpha(alpha)))
+            }
+            Value::EmptyListLit(n) => {
+                rc(ExprF::EmptyListLit(n.normalize_to_expr_maybe_alpha(alpha)))
+            }
+            Value::NEListLit(elts) => rc(ExprF::NEListLit(
+                elts.into_iter()
+                    .map(|n| n.normalize_to_expr_maybe_alpha(alpha))
+                    .collect(),
+            )),
+            Value::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(
+                kts.iter()
+                    .map(|(k, v)| {
+                        (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
+                    })
+                    .collect(),
+            )),
+            Value::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(),
+            )),
+            Value::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()))
+            }
+            Value::UnionLit(l, v, kts) => rc(ExprF::UnionLit(
+                l.clone(),
+                v.normalize_to_expr_maybe_alpha(alpha),
+                kts.iter()
+                    .map(|(k, v)| {
+                        (
+                            k.clone(),
+                            v.as_ref().map(|v| {
+                                v.normalize_to_expr_maybe_alpha(alpha)
+                            }),
+                        )
+                    })
+                    .collect(),
+            )),
+            Value::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(),
+                ))
+            }
+            Value::PartialExpr(e) => {
+                rc(e.map_ref_simple(|v| v.normalize_to_expr_maybe_alpha(alpha)))
+            }
+        }
+    }
+
+    // Deprecated
+    fn normalize(&self) -> Value {
+        let mut v = self.clone();
+        v.normalize_mut();
+        v
+    }
+
+    pub(crate) fn normalize_mut(&mut self) {
+        match self {
+            Value::NaturalSuccClosure
+            | Value::Var(_)
+            | Value::Const(_)
+            | Value::BoolLit(_)
+            | Value::NaturalLit(_)
+            | Value::IntegerLit(_) => {}
+
+            Value::EmptyOptionalLit(tth)
+            | Value::OptionalSomeClosure(tth)
+            | Value::EmptyListLit(tth) => {
+                tth.normalize_mut();
+            }
+
+            Value::NEOptionalLit(th) => {
+                th.normalize_mut();
+            }
+            Value::Lam(_, t, e) => {
+                t.normalize_mut();
+                e.normalize_mut();
+            }
+            Value::Pi(_, t, e) => {
+                t.normalize_mut();
+                e.normalize_mut();
+            }
+            Value::AppliedBuiltin(_, args) => {
+                for x in args.iter_mut() {
+                    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();
+                }
+            }
+            Value::RecordLit(kvs) => {
+                for x in kvs.values_mut() {
+                    x.normalize_mut();
+                }
+            }
+            Value::RecordType(kvs) => {
+                for x in kvs.values_mut() {
+                    x.normalize_mut();
+                }
+            }
+            Value::UnionType(kts) | Value::UnionConstructor(_, kts) => {
+                for x in kts.values_mut().flat_map(|opt| opt) {
+                    x.normalize_mut();
+                }
+            }
+            Value::UnionLit(_, v, kts) => {
+                v.normalize_mut();
+                for x in kts.values_mut().flat_map(|opt| opt) {
+                    x.normalize_mut();
+                }
+            }
+            Value::TextLit(elts) => {
+                for x in elts.iter_mut() {
+                    use InterpolatedTextContents::{Expr, Text};
+                    match x {
+                        Expr(n) => n.normalize_mut(),
+                        Text(_) => {}
+                    }
+                }
+            }
+            Value::PartialExpr(e) => {
+                // TODO: need map_mut_simple
+                e.map_ref_simple(|v| {
+                    v.normalize_nf();
+                });
+            }
+        }
+    }
+
+    /// Apply to a value
+    pub(crate) fn app(self, val: Value) -> Value {
+        self.app_val(val)
+    }
+
+    /// Apply to a value
+    pub(crate) fn app_val(self, val: Value) -> Value {
+        self.app_thunk(val.into_thunk())
+    }
+
+    /// Apply to a thunk
+    pub(crate) fn app_thunk(self, th: Thunk) -> Value {
+        Thunk::from_value(self).app_thunk(th)
+    }
+
+    pub(crate) fn from_builtin(b: Builtin) -> Value {
+        Value::AppliedBuiltin(b, vec![])
+    }
+
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
+        match self {
+            Value::Lam(x, t, e) => Value::Lam(
+                x.clone(),
+                t.shift(delta, var),
+                e.shift(delta, &var.shift(1, &x.into())),
+            ),
+            Value::AppliedBuiltin(b, args) => Value::AppliedBuiltin(
+                *b,
+                args.iter().map(|v| v.shift(delta, var)).collect(),
+            ),
+            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| v.shift(delta, var)),
+            ),
+            Value::Pi(x, t, e) => Value::Pi(
+                x.clone(),
+                t.shift(delta, var),
+                e.shift(delta, &var.shift(1, &x.into())),
+            ),
+            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::EmptyOptionalLit(tth) => {
+                Value::EmptyOptionalLit(tth.shift(delta, var))
+            }
+            Value::NEOptionalLit(th) => {
+                Value::NEOptionalLit(th.shift(delta, var))
+            }
+            Value::EmptyListLit(tth) => {
+                Value::EmptyListLit(tth.shift(delta, var))
+            }
+            Value::NEListLit(elts) => Value::NEListLit(
+                elts.iter().map(|v| v.shift(delta, var)).collect(),
+            ),
+            Value::RecordLit(kvs) => Value::RecordLit(
+                kvs.iter()
+                    .map(|(k, v)| (k.clone(), v.shift(delta, var)))
+                    .collect(),
+            ),
+            Value::RecordType(kvs) => Value::RecordType(
+                kvs.iter()
+                    .map(|(k, v)| (k.clone(), v.shift(delta, var)))
+                    .collect(),
+            ),
+            Value::UnionType(kts) => Value::UnionType(
+                kts.iter()
+                    .map(|(k, v)| {
+                        (k.clone(), v.as_ref().map(|v| v.shift(delta, var)))
+                    })
+                    .collect(),
+            ),
+            Value::UnionConstructor(x, kts) => Value::UnionConstructor(
+                x.clone(),
+                kts.iter()
+                    .map(|(k, v)| {
+                        (k.clone(), v.as_ref().map(|v| v.shift(delta, var)))
+                    })
+                    .collect(),
+            ),
+            Value::UnionLit(x, v, kts) => Value::UnionLit(
+                x.clone(),
+                v.shift(delta, var),
+                kts.iter()
+                    .map(|(k, v)| {
+                        (k.clone(), v.as_ref().map(|v| v.shift(delta, var)))
+                    })
+                    .collect(),
+            ),
+            Value::TextLit(elts) => Value::TextLit(
+                elts.iter()
+                    .map(|contents| {
+                        use InterpolatedTextContents::{Expr, Text};
+                        match contents {
+                            Expr(th) => Expr(th.shift(delta, var)),
+                            Text(s) => Text(s.clone()),
+                        }
+                    })
+                    .collect(),
+            ),
+            Value::PartialExpr(e) => {
+                Value::PartialExpr(e.map_ref_with_special_handling_of_binders(
+                    |v| v.shift(delta, var),
+                    |x, v| v.shift(delta, &var.shift(1, &x.into())),
+                    X::clone,
+                    Label::clone,
+                ))
+            }
+        }
+    }
+
+    pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        match self {
+            // Retry normalizing since substituting may allow progress
+            Value::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) => {
+                normalize_one_layer(e.map_ref_with_special_handling_of_binders(
+                    |v| v.subst_shift(var, val),
+                    |x, v| {
+                        v.subst_shift(
+                            &var.shift(1, &x.into()),
+                            &val.shift(1, &x.into()),
+                        )
+                    },
+                    X::clone,
+                    Label::clone,
+                ))
+            }
+            // Retry normalizing since substituting may allow progress
+            Value::TextLit(elts) => {
+                Value::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()),
+                    }
+                })))
+            }
+            Value::Lam(x, t, e) => Value::Lam(
+                x.clone(),
+                t.subst_shift(var, val),
+                e.subst_shift(
+                    &var.shift(1, &x.into()),
+                    &val.shift(1, &x.into()),
+                ),
+            ),
+            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),
+                e.subst_shift(
+                    &var.shift(1, &x.into()),
+                    &val.shift(1, &x.into()),
+                ),
+            ),
+            Value::Var(v) if v == var => val.to_value().clone(),
+            Value::Var(v) => Value::Var(v.shift(-1, 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::EmptyOptionalLit(tth) => {
+                Value::EmptyOptionalLit(tth.subst_shift(var, val))
+            }
+            Value::NEOptionalLit(th) => {
+                Value::NEOptionalLit(th.subst_shift(var, val))
+            }
+            Value::EmptyListLit(tth) => {
+                Value::EmptyListLit(tth.subst_shift(var, val))
+            }
+            Value::NEListLit(elts) => Value::NEListLit(
+                elts.iter().map(|v| v.subst_shift(var, val)).collect(),
+            ),
+            Value::RecordLit(kvs) => Value::RecordLit(
+                kvs.iter()
+                    .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
+                    .collect(),
+            ),
+            Value::RecordType(kvs) => Value::RecordType(
+                kvs.iter()
+                    .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
+                    .collect(),
+            ),
+            Value::UnionType(kts) => Value::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(
+                x.clone(),
+                kts.iter()
+                    .map(|(k, v)| {
+                        (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
+                    })
+                    .collect(),
+            ),
+            Value::UnionLit(x, v, kts) => Value::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(),
+            ),
+        }
+    }
+}
+
+mod thunk {
+    use super::{
+        apply_any, normalize_whnf, AlphaVar, InputSubExpr,
+        NormalizationContext, OutputSubExpr, Value,
+    };
+    use crate::phase::Typed;
+    use std::cell::{Ref, RefCell};
+    use std::rc::Rc;
+
+    #[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)]
+    enum ThunkInternal {
+        /// Non-normalized value alongside a normalization context
+        Unnormalized(NormalizationContext, InputSubExpr),
+        /// Partially normalized value.
+        /// Invariant: if the marker is `NF`, the value must be fully normalized
+        Value(Marker, Value),
+    }
+
+    /// Stores a possibl unevaluated value. Uses RefCell to ensure that
+    /// the value gets normalized at most once.
+    #[derive(Debug, Clone)]
+    pub struct Thunk(Rc<RefCell<ThunkInternal>>);
+
+    impl ThunkInternal {
+        fn into_thunk(self) -> Thunk {
+            Thunk(Rc::new(RefCell::new(self)))
+        }
+
+        fn normalize_whnf(&mut self) {
+            match self {
+                ThunkInternal::Unnormalized(ctx, e) => {
+                    *self = ThunkInternal::Value(
+                        WHNF,
+                        normalize_whnf(ctx.clone(), e.clone()),
+                    )
+                }
+                // Already at least in WHNF
+                ThunkInternal::Value(_, _) => {}
+            }
+        }
+
+        fn normalize_nf(&mut self) {
+            match self {
+                ThunkInternal::Unnormalized(_, _) => {
+                    self.normalize_whnf();
+                    self.normalize_nf();
+                }
+                ThunkInternal::Value(m @ WHNF, v) => {
+                    v.normalize_mut();
+                    *m = NF;
+                }
+                // Already in NF
+                ThunkInternal::Value(NF, _) => {}
+            }
+        }
+
+        // Always use normalize_whnf before
+        fn as_whnf(&self) -> &Value {
+            match self {
+                ThunkInternal::Unnormalized(_, _) => unreachable!(),
+                ThunkInternal::Value(_, v) => v,
+            }
+        }
+
+        // Always use normalize_nf before
+        fn as_nf(&self) -> &Value {
+            match self {
+                ThunkInternal::Unnormalized(_, _) => unreachable!(),
+                ThunkInternal::Value(WHNF, _) => unreachable!(),
+                ThunkInternal::Value(NF, v) => v,
+            }
+        }
+
+        fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
+            match self {
+                ThunkInternal::Unnormalized(ctx, e) => {
+                    ThunkInternal::Unnormalized(
+                        ctx.shift(delta, var),
+                        e.clone(),
+                    )
+                }
+                ThunkInternal::Value(m, v) => {
+                    ThunkInternal::Value(*m, v.shift(delta, var))
+                }
+            }
+        }
+
+        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::Value(_, v) => {
+                    // The resulting value may not stay in normal form after substitution
+                    ThunkInternal::Value(WHNF, v.subst_shift(var, val))
+                }
+            }
+        }
+    }
+
+    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()
+        }
+
+        pub(crate) fn from_normalized_expr(e: OutputSubExpr) -> Thunk {
+            Thunk::new(
+                NormalizationContext::new(),
+                e.embed_absurd().note_absurd(),
+            )
+        }
+
+        // Normalizes contents to normal form; faster than `normalize_nf` if
+        // no one else shares this thunk
+        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(),
+                // Otherwise mutate through the refcell
+                None => self.0.borrow_mut().normalize_nf(),
+            }
+        }
+
+        fn do_normalize_whnf(&self) {
+            let borrow = self.0.borrow();
+            match &*borrow {
+                ThunkInternal::Unnormalized(_, _) => {
+                    drop(borrow);
+                    self.0.borrow_mut().normalize_whnf();
+                }
+                // Already at least in WHNF
+                ThunkInternal::Value(_, _) => {}
+            }
+        }
+
+        fn do_normalize_nf(&self) {
+            let borrow = self.0.borrow();
+            match &*borrow {
+                ThunkInternal::Unnormalized(_, _)
+                | ThunkInternal::Value(WHNF, _) => {
+                    drop(borrow);
+                    self.0.borrow_mut().normalize_nf();
+                }
+                // Already in NF
+                ThunkInternal::Value(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> {
+            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> {
+            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 normalize_to_expr(&self) -> OutputSubExpr {
+            self.normalize_to_expr_maybe_alpha(false)
+        }
+
+        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: Value) -> Value {
+            self.app_thunk(val.into_thunk())
+        }
+
+        pub(crate) fn app_thunk(&self, th: Thunk) -> Value {
+            apply_any(self.clone(), th)
+        }
+
+        pub(crate) fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
+            self.0.borrow().shift(delta, var).into_thunk()
+        }
+
+        pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+            self.0.borrow().subst_shift(var, val).into_thunk()
+        }
+    }
+
+    impl std::cmp::PartialEq for Thunk {
+        fn eq(&self, other: &Self) -> bool {
+            &*self.as_value() == &*other.as_value()
+        }
+    }
+    impl std::cmp::Eq for Thunk {}
+}
+
+pub(crate) use thunk::Thunk;
+
+/// A thunk in type position.
+#[derive(Debug, Clone)]
+pub(crate) enum TypeThunk {
+    Thunk(Thunk),
+    Type(Type),
+}
+
+impl TypeThunk {
+    fn from_value(v: Value) -> TypeThunk {
+        TypeThunk::from_thunk(Thunk::from_value(v))
+    }
+
+    fn from_thunk(th: Thunk) -> TypeThunk {
+        TypeThunk::Thunk(th)
+    }
+
+    pub(crate) fn from_type(t: Type) -> TypeThunk {
+        TypeThunk::Type(t)
+    }
+
+    fn normalize_mut(&mut self) {
+        match self {
+            TypeThunk::Thunk(th) => th.normalize_mut(),
+            TypeThunk::Type(_) => {}
+        }
+    }
+
+    pub(crate) fn normalize_nf(&self) -> Value {
+        match self {
+            TypeThunk::Thunk(th) => th.normalize_nf().clone(),
+            TypeThunk::Type(t) => t.to_value().normalize(),
+        }
+    }
+
+    pub(crate) fn to_value(&self) -> Value {
+        match self {
+            TypeThunk::Thunk(th) => th.to_value(),
+            TypeThunk::Type(t) => t.to_value(),
+        }
+    }
+
+    pub(crate) fn normalize_to_expr_maybe_alpha(
+        &self,
+        alpha: bool,
+    ) -> OutputSubExpr {
+        self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
+    }
+
+    fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
+        match self {
+            TypeThunk::Thunk(th) => TypeThunk::Thunk(th.shift(delta, var)),
+            TypeThunk::Type(t) => TypeThunk::Type(t.shift(delta, var)),
+        }
+    }
+
+    pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
+        match self {
+            TypeThunk::Thunk(th) => TypeThunk::Thunk(th.subst_shift(var, val)),
+            TypeThunk::Type(t) => TypeThunk::Type(t.subst_shift(var, val)),
+        }
+    }
+}
+
+impl std::cmp::PartialEq for TypeThunk {
+    fn eq(&self, other: &Self) -> bool {
+        self.to_value() == other.to_value()
+    }
+}
+impl std::cmp::Eq for TypeThunk {}
+
+fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
+    use dhall_syntax::Builtin::*;
+    use 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()))))
+        }
+        (NaturalIsZero, [n, r..]) => match &*n.as_value() {
+            NaturalLit(n) => Ok((r, BoolLit(*n == 0))),
+            _ => Err(()),
+        },
+        (NaturalEven, [n, r..]) => match &*n.as_value() {
+            NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0))),
+            _ => Err(()),
+        },
+        (NaturalOdd, [n, r..]) => match &*n.as_value() {
+            NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0))),
+            _ => Err(()),
+        },
+        (NaturalToInteger, [n, r..]) => match &*n.as_value() {
+            NaturalLit(n) => Ok((r, IntegerLit(*n as isize))),
+            _ => Err(()),
+        },
+        (NaturalShow, [n, r..]) => match &*n.as_value() {
+            NaturalLit(n) => Ok((
+                r,
+                TextLit(vec![InterpolatedTextContents::Text(n.to_string())]),
+            )),
+            _ => Err(()),
+        },
+        (ListLength, [_, l, r..]) => match &*l.as_value() {
+            EmptyListLit(_) => Ok((r, NaturalLit(0))),
+            NEListLit(xs) => Ok((r, NaturalLit(xs.len()))),
+            _ => Err(()),
+        },
+        (ListHead, [_, l, r..]) => match &*l.as_value() {
+            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() {
+            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() {
+            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() {
+            EmptyListLit(t) => {
+                let mut kts = BTreeMap::new();
+                kts.insert(
+                    "index".into(),
+                    TypeThunk::from_value(Value::from_builtin(Natural)),
+                );
+                kts.insert("value".into(), t.clone());
+                Ok((r, EmptyListLit(TypeThunk::from_value(RecordType(kts)))))
+            }
+            NEListLit(xs) => {
+                let xs = xs
+                    .iter()
+                    .enumerate()
+                    .map(|(i, e)| {
+                        let i = NaturalLit(i);
+                        let mut kvs = BTreeMap::new();
+                        kvs.insert("index".into(), Thunk::from_value(i));
+                        kvs.insert("value".into(), e.clone());
+                        Thunk::from_value(RecordLit(kvs))
+                    })
+                    .collect();
+                Ok((r, NEListLit(xs)))
+            }
+            _ => Err(()),
+        },
+        (ListBuild, [t, f, r..]) => match &*f.as_value() {
+            // fold/build fusion
+            Value::AppliedBuiltin(ListFold, args) => {
+                if args.len() >= 2 {
+                    Ok((r, args[1].to_value()))
+                } else {
+                    // Do we really need to handle this case ?
+                    unimplemented!()
+                }
+            }
+            _ => Ok((
+                r,
+                f.app_val(Value::from_builtin(List).app_thunk(t.clone()))
+                    .app_val(ListConsClosure(
+                        TypeThunk::from_thunk(t.clone()),
+                        None,
+                    ))
+                    .app_val(EmptyListLit(TypeThunk::from_thunk(t.clone()))),
+            )),
+        },
+        (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_value() {
+            EmptyListLit(_) => Ok((r, nil.to_value())),
+            NEListLit(xs) => {
+                let mut v = nil.clone();
+                for x in xs.iter().rev() {
+                    v = cons
+                        .clone()
+                        .app_thunk(x.clone())
+                        .app_thunk(v)
+                        .into_thunk();
+                }
+                Ok((r, v.to_value()))
+            }
+            _ => Err(()),
+        },
+        (OptionalBuild, [t, f, r..]) => match &*f.as_value() {
+            // fold/build fusion
+            Value::AppliedBuiltin(OptionalFold, args) => {
+                if args.len() >= 2 {
+                    Ok((r, args[1].to_value()))
+                } else {
+                    // Do we really need to handle this case ?
+                    unimplemented!()
+                }
+            }
+            _ => Ok((
+                r,
+                f.app_val(Value::from_builtin(Optional).app_thunk(t.clone()))
+                    .app_val(OptionalSomeClosure(TypeThunk::from_thunk(
+                        t.clone(),
+                    )))
+                    .app_val(EmptyOptionalLit(TypeThunk::from_thunk(
+                        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() {
+            // fold/build fusion
+            Value::AppliedBuiltin(NaturalFold, args) => {
+                if args.len() >= 1 {
+                    Ok((r, args[0].to_value()))
+                } else {
+                    // Do we really need to handle this case ?
+                    unimplemented!()
+                }
+            }
+            _ => Ok((
+                r,
+                f.app_val(Value::from_builtin(Natural))
+                    .app_val(NaturalSuccClosure)
+                    .app_val(NaturalLit(0)),
+            )),
+        },
+        (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_value() {
+            NaturalLit(0) => Ok((r, zero.to_value())),
+            NaturalLit(n) => {
+                let fold = Value::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)))
+            }
+            _ => Err(()),
+        },
+        _ => Err(()),
+    };
+    match ret {
+        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
+        }
+        Err(()) => AppliedBuiltin(b, args),
+    }
+}
+
+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();
+    match &*f_borrow {
+        Value::Lam(x, _, e) => {
+            let val = Typed::from_thunk_untyped(a);
+            e.subst_shift(&x.into(), &val).to_value()
+        }
+        Value::AppliedBuiltin(b, args) => {
+            use std::iter::once;
+            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())
+        }
+        _ => {
+            drop(f_borrow);
+            fallback(f, a)
+        }
+    }
+}
+
+fn squash_textlit(
+    elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>,
+) -> Vec<InterpolatedTextContents<Thunk>> {
+    use std::mem::replace;
+    use InterpolatedTextContents::{Expr, Text};
+
+    fn inner(
+        elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>,
+        crnt_str: &mut String,
+        ret: &mut Vec<InterpolatedTextContents<Thunk>>,
+    ) {
+        for contents in elts {
+            match contents {
+                Text(s) => crnt_str.push_str(&s),
+                Expr(e) => {
+                    let e_borrow = e.as_value();
+                    match &*e_borrow {
+                        Value::TextLit(elts2) => {
+                            inner(elts2.iter().cloned(), crnt_str, ret)
+                        }
+                        _ => {
+                            drop(e_borrow);
+                            if !crnt_str.is_empty() {
+                                ret.push(Text(replace(crnt_str, String::new())))
+                            }
+                            ret.push(Expr(e.clone()))
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    let mut crnt_str = String::new();
+    let mut ret = Vec::new();
+    inner(elts, &mut crnt_str, &mut ret);
+    if !crnt_str.is_empty() {
+        ret.push(Text(replace(&mut crnt_str, String::new())))
+    }
+    ret
+}
+
+/// Reduces the imput expression to a Value. Evaluates as little as possible.
+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, Label, X> =
+        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!(),
+            Label::clone,
+        );
+
+    normalize_one_layer(expr)
+}
+
+fn normalize_one_layer(expr: ExprF<Thunk, Label, X>) -> Value {
+    use Value::{
+        BoolLit, EmptyListLit, EmptyOptionalLit, IntegerLit, Lam, NEListLit,
+        NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType, TextLit,
+        UnionConstructor, UnionLit, UnionType,
+    };
+
+    // Small helper enum to avoid repetition
+    enum Ret<'a> {
+        RetValue(Value),
+        RetThunk(Thunk),
+        RetThunkRef(&'a Thunk),
+        RetExpr(ExprF<Thunk, Label, X>),
+    }
+    use Ret::{RetExpr, RetThunk, RetThunkRef, RetValue};
+
+    let ret = match expr {
+        ExprF::Embed(_) => unreachable!(),
+        ExprF::Var(_) => unreachable!(),
+        ExprF::Annot(x, _) => RetThunk(x),
+        ExprF::Lam(x, t, e) => RetValue(Lam(x.into(), t, e)),
+        ExprF::Pi(x, t, e) => RetValue(Pi(
+            x.into(),
+            TypeThunk::from_thunk(t),
+            TypeThunk::from_thunk(e),
+        )),
+        ExprF::Let(x, _, v, b) => {
+            let v = Typed::from_thunk_untyped(v);
+            RetThunk(b.subst_shift(&x.into(), &v))
+        }
+        ExprF::App(v, a) => RetValue(v.app_thunk(a)),
+        ExprF::Builtin(b) => RetValue(Value::from_builtin(b)),
+        ExprF::Const(c) => RetValue(Value::Const(c)),
+        ExprF::BoolLit(b) => RetValue(BoolLit(b)),
+        ExprF::NaturalLit(n) => RetValue(NaturalLit(n)),
+        ExprF::IntegerLit(n) => RetValue(IntegerLit(n)),
+        ExprF::DoubleLit(_) => RetExpr(expr),
+        ExprF::OldOptionalLit(None, t) => {
+            RetValue(EmptyOptionalLit(TypeThunk::from_thunk(t)))
+        }
+        ExprF::OldOptionalLit(Some(e), _) => RetValue(NEOptionalLit(e)),
+        ExprF::SomeLit(e) => RetValue(NEOptionalLit(e)),
+        ExprF::EmptyListLit(t) => {
+            RetValue(EmptyListLit(TypeThunk::from_thunk(t)))
+        }
+        ExprF::NEListLit(elts) => {
+            RetValue(NEListLit(elts.into_iter().collect()))
+        }
+        ExprF::RecordLit(kvs) => RetValue(RecordLit(kvs.into_iter().collect())),
+        ExprF::RecordType(kts) => RetValue(RecordType(
+            kts.into_iter()
+                .map(|(k, t)| (k, TypeThunk::from_thunk(t)))
+                .collect(),
+        )),
+        ExprF::UnionLit(l, x, kts) => RetValue(UnionLit(
+            l,
+            x,
+            kts.into_iter()
+                .map(|(k, t)| (k, t.map(|t| TypeThunk::from_thunk(t))))
+                .collect(),
+        )),
+        ExprF::UnionType(kts) => RetValue(UnionType(
+            kts.into_iter()
+                .map(|(k, t)| (k, t.map(|t| TypeThunk::from_thunk(t))))
+                .collect(),
+        )),
+        ExprF::TextLit(elts) => {
+            use InterpolatedTextContents::Expr;
+            let elts: Vec<_> = squash_textlit(elts.into_iter());
+            // Simplify bare interpolation
+            if let [Expr(th)] = elts.as_slice() {
+                RetThunk(th.clone())
+            } else {
+                RetValue(TextLit(elts))
+            }
+        }
+        ExprF::BoolIf(ref b, ref e1, ref e2) => {
+            let b_borrow = b.as_value();
+            match &*b_borrow {
+                BoolLit(true) => RetThunkRef(e1),
+                BoolLit(false) => RetThunkRef(e2),
+                _ => {
+                    let e1_borrow = e1.as_value();
+                    let e2_borrow = e2.as_value();
+                    match (&*e1_borrow, &*e2_borrow) {
+                        // Simplify `if b then True else False`
+                        (BoolLit(true), BoolLit(false)) => RetThunkRef(b),
+                        _ if e1 == e2 => RetThunkRef(e1),
+                        _ => {
+                            drop(b_borrow);
+                            drop(e1_borrow);
+                            drop(e2_borrow);
+                            RetExpr(expr)
+                        }
+                    }
+                }
+            }
+        }
+        ExprF::BinOp(o, ref x, ref y) => {
+            use BinOp::{
+                BoolAnd, BoolEQ, BoolNE, BoolOr, ListAppend, NaturalPlus,
+                NaturalTimes, TextAppend,
+            };
+            let x_borrow = x.as_value();
+            let y_borrow = y.as_value();
+            match (o, &*x_borrow, &*y_borrow) {
+                (BoolAnd, BoolLit(true), _) => RetThunkRef(y),
+                (BoolAnd, _, BoolLit(true)) => RetThunkRef(x),
+                (BoolAnd, BoolLit(false), _) => RetValue(BoolLit(false)),
+                (BoolAnd, _, BoolLit(false)) => RetValue(BoolLit(false)),
+                (BoolAnd, _, _) if x == y => RetThunkRef(x),
+                (BoolOr, BoolLit(true), _) => RetValue(BoolLit(true)),
+                (BoolOr, _, BoolLit(true)) => RetValue(BoolLit(true)),
+                (BoolOr, BoolLit(false), _) => RetThunkRef(y),
+                (BoolOr, _, BoolLit(false)) => RetThunkRef(x),
+                (BoolOr, _, _) if x == y => RetThunkRef(x),
+                (BoolEQ, BoolLit(true), _) => RetThunkRef(y),
+                (BoolEQ, _, BoolLit(true)) => RetThunkRef(x),
+                (BoolEQ, BoolLit(x), BoolLit(y)) => RetValue(BoolLit(x == y)),
+                (BoolEQ, _, _) if x == y => RetValue(BoolLit(true)),
+                (BoolNE, BoolLit(false), _) => RetThunkRef(y),
+                (BoolNE, _, BoolLit(false)) => RetThunkRef(x),
+                (BoolNE, BoolLit(x), BoolLit(y)) => RetValue(BoolLit(x != y)),
+                (BoolNE, _, _) if x == y => RetValue(BoolLit(false)),
+
+                (NaturalPlus, NaturalLit(0), _) => RetThunkRef(y),
+                (NaturalPlus, _, NaturalLit(0)) => RetThunkRef(x),
+                (NaturalPlus, NaturalLit(x), NaturalLit(y)) => {
+                    RetValue(NaturalLit(x + y))
+                }
+                (NaturalTimes, NaturalLit(0), _) => RetValue(NaturalLit(0)),
+                (NaturalTimes, _, NaturalLit(0)) => RetValue(NaturalLit(0)),
+                (NaturalTimes, NaturalLit(1), _) => RetThunkRef(y),
+                (NaturalTimes, _, NaturalLit(1)) => RetThunkRef(x),
+                (NaturalTimes, NaturalLit(x), NaturalLit(y)) => {
+                    RetValue(NaturalLit(x * y))
+                }
+
+                (ListAppend, EmptyListLit(_), _) => RetThunkRef(y),
+                (ListAppend, _, EmptyListLit(_)) => RetThunkRef(x),
+                (ListAppend, NEListLit(xs), NEListLit(ys)) => RetValue(
+                    NEListLit(xs.iter().chain(ys.iter()).cloned().collect()),
+                ),
+
+                (TextAppend, TextLit(x), _) if x.is_empty() => RetThunkRef(y),
+                (TextAppend, _, TextLit(y)) if y.is_empty() => RetThunkRef(x),
+                (TextAppend, TextLit(x), TextLit(y)) => RetValue(TextLit(
+                    squash_textlit(x.iter().chain(y.iter()).cloned()),
+                )),
+                (TextAppend, TextLit(x), _) => {
+                    use std::iter::once;
+                    let y = InterpolatedTextContents::Expr(y.clone());
+                    RetValue(TextLit(squash_textlit(
+                        x.iter().cloned().chain(once(y)),
+                    )))
+                }
+                (TextAppend, _, TextLit(y)) => {
+                    use std::iter::once;
+                    let x = InterpolatedTextContents::Expr(x.clone());
+                    RetValue(TextLit(squash_textlit(
+                        once(x).chain(y.iter().cloned()),
+                    )))
+                }
+
+                _ => {
+                    drop(x_borrow);
+                    drop(y_borrow);
+                    RetExpr(expr)
+                }
+            }
+        }
+
+        ExprF::Projection(_, ls) if ls.is_empty() => {
+            RetValue(RecordLit(std::collections::BTreeMap::new()))
+        }
+        ExprF::Projection(ref v, ref ls) => {
+            let v_borrow = v.as_value();
+            match &*v_borrow {
+                RecordLit(kvs) => RetValue(RecordLit(
+                    ls.iter()
+                        .filter_map(|l| {
+                            kvs.get(l).map(|x| (l.clone(), x.clone()))
+                        })
+                        .collect(),
+                )),
+                _ => {
+                    drop(v_borrow);
+                    RetExpr(expr)
+                }
+            }
+        }
+        ExprF::Field(ref v, ref l) => {
+            let v_borrow = v.as_value();
+            match &*v_borrow {
+                RecordLit(kvs) => match kvs.get(l) {
+                    Some(r) => RetThunk(r.clone()),
+                    None => {
+                        drop(v_borrow);
+                        RetExpr(expr)
+                    }
+                },
+                UnionType(kts) => {
+                    RetValue(UnionConstructor(l.clone(), kts.clone()))
+                }
+                _ => {
+                    drop(v_borrow);
+                    RetExpr(expr)
+                }
+            }
+        }
+
+        ExprF::Merge(ref handlers, ref variant, _) => {
+            let handlers_borrow = handlers.as_value();
+            let variant_borrow = variant.as_value();
+            match (&*handlers_borrow, &*variant_borrow) {
+                (RecordLit(kvs), UnionConstructor(l, _)) => match kvs.get(l) {
+                    Some(h) => RetThunk(h.clone()),
+                    None => {
+                        drop(handlers_borrow);
+                        drop(variant_borrow);
+                        RetExpr(expr)
+                    }
+                },
+                (RecordLit(kvs), UnionLit(l, v, _)) => match kvs.get(l) {
+                    Some(h) => RetValue(h.app_thunk(v.clone())),
+                    None => {
+                        drop(handlers_borrow);
+                        drop(variant_borrow);
+                        RetExpr(expr)
+                    }
+                },
+                _ => {
+                    drop(handlers_borrow);
+                    drop(variant_borrow);
+                    RetExpr(expr)
+                }
+            }
+        }
+    };
+
+    match ret {
+        RetValue(v) => v,
+        RetThunk(th) => th.to_value(),
+        RetThunkRef(th) => th.to_value(),
+        RetExpr(expr) => Value::PartialExpr(expr),
+    }
+}
+
+#[cfg(test)]
+mod spec_tests {
+    #![rustfmt::skip]
+
+    macro_rules! norm {
+        ($name:ident, $path:expr) => {
+            make_spec_test!(Normalization, Success, $name, $path);
+        };
+    }
+
+    macro_rules! alpha_norm {
+        ($name:ident, $path:expr) => {
+            make_spec_test!(AlphaNormalization, Success, $name, $path);
+        };
+    }
+
+    norm!(success_haskell_tutorial_access_0, "haskell-tutorial/access/0");
+    norm!(success_haskell_tutorial_access_1, "haskell-tutorial/access/1");
+    // norm!(success_haskell_tutorial_combineTypes_0, "haskell-tutorial/combineTypes/0");
+    // norm!(success_haskell_tutorial_combineTypes_1, "haskell-tutorial/combineTypes/1");
+    // norm!(success_haskell_tutorial_prefer_0, "haskell-tutorial/prefer/0");
+    norm!(success_haskell_tutorial_projection_0, "haskell-tutorial/projection/0");
+
+    norm!(success_prelude_Bool_and_0, "prelude/Bool/and/0");
+    norm!(success_prelude_Bool_and_1, "prelude/Bool/and/1");
+    norm!(success_prelude_Bool_build_0, "prelude/Bool/build/0");
+    norm!(success_prelude_Bool_build_1, "prelude/Bool/build/1");
+    norm!(success_prelude_Bool_even_0, "prelude/Bool/even/0");
+    norm!(success_prelude_Bool_even_1, "prelude/Bool/even/1");
+    norm!(success_prelude_Bool_even_2, "prelude/Bool/even/2");
+    norm!(success_prelude_Bool_even_3, "prelude/Bool/even/3");
+    norm!(success_prelude_Bool_fold_0, "prelude/Bool/fold/0");
+    norm!(success_prelude_Bool_fold_1, "prelude/Bool/fold/1");
+    norm!(success_prelude_Bool_not_0, "prelude/Bool/not/0");
+    norm!(success_prelude_Bool_not_1, "prelude/Bool/not/1");
+    norm!(success_prelude_Bool_odd_0, "prelude/Bool/odd/0");
+    norm!(success_prelude_Bool_odd_1, "prelude/Bool/odd/1");
+    norm!(success_prelude_Bool_odd_2, "prelude/Bool/odd/2");
+    norm!(success_prelude_Bool_odd_3, "prelude/Bool/odd/3");
+    norm!(success_prelude_Bool_or_0, "prelude/Bool/or/0");
+    norm!(success_prelude_Bool_or_1, "prelude/Bool/or/1");
+    norm!(success_prelude_Bool_show_0, "prelude/Bool/show/0");
+    norm!(success_prelude_Bool_show_1, "prelude/Bool/show/1");
+    // norm!(success_prelude_Double_show_0, "prelude/Double/show/0");
+    // norm!(success_prelude_Double_show_1, "prelude/Double/show/1");
+    // norm!(success_prelude_Integer_show_0, "prelude/Integer/show/0");
+    // norm!(success_prelude_Integer_show_1, "prelude/Integer/show/1");
+    // norm!(success_prelude_Integer_toDouble_0, "prelude/Integer/toDouble/0");
+    // norm!(success_prelude_Integer_toDouble_1, "prelude/Integer/toDouble/1");
+    norm!(success_prelude_List_all_0, "prelude/List/all/0");
+    norm!(success_prelude_List_all_1, "prelude/List/all/1");
+    norm!(success_prelude_List_any_0, "prelude/List/any/0");
+    norm!(success_prelude_List_any_1, "prelude/List/any/1");
+    norm!(success_prelude_List_build_0, "prelude/List/build/0");
+    norm!(success_prelude_List_build_1, "prelude/List/build/1");
+    norm!(success_prelude_List_concat_0, "prelude/List/concat/0");
+    norm!(success_prelude_List_concat_1, "prelude/List/concat/1");
+    norm!(success_prelude_List_concatMap_0, "prelude/List/concatMap/0");
+    norm!(success_prelude_List_concatMap_1, "prelude/List/concatMap/1");
+    norm!(success_prelude_List_filter_0, "prelude/List/filter/0");
+    norm!(success_prelude_List_filter_1, "prelude/List/filter/1");
+    norm!(success_prelude_List_fold_0, "prelude/List/fold/0");
+    norm!(success_prelude_List_fold_1, "prelude/List/fold/1");
+    norm!(success_prelude_List_fold_2, "prelude/List/fold/2");
+    norm!(success_prelude_List_generate_0, "prelude/List/generate/0");
+    norm!(success_prelude_List_generate_1, "prelude/List/generate/1");
+    norm!(success_prelude_List_head_0, "prelude/List/head/0");
+    norm!(success_prelude_List_head_1, "prelude/List/head/1");
+    norm!(success_prelude_List_indexed_0, "prelude/List/indexed/0");
+    norm!(success_prelude_List_indexed_1, "prelude/List/indexed/1");
+    norm!(success_prelude_List_iterate_0, "prelude/List/iterate/0");
+    norm!(success_prelude_List_iterate_1, "prelude/List/iterate/1");
+    norm!(success_prelude_List_last_0, "prelude/List/last/0");
+    norm!(success_prelude_List_last_1, "prelude/List/last/1");
+    norm!(success_prelude_List_length_0, "prelude/List/length/0");
+    norm!(success_prelude_List_length_1, "prelude/List/length/1");
+    norm!(success_prelude_List_map_0, "prelude/List/map/0");
+    norm!(success_prelude_List_map_1, "prelude/List/map/1");
+    norm!(success_prelude_List_null_0, "prelude/List/null/0");
+    norm!(success_prelude_List_null_1, "prelude/List/null/1");
+    norm!(success_prelude_List_replicate_0, "prelude/List/replicate/0");
+    norm!(success_prelude_List_replicate_1, "prelude/List/replicate/1");
+    norm!(success_prelude_List_reverse_0, "prelude/List/reverse/0");
+    norm!(success_prelude_List_reverse_1, "prelude/List/reverse/1");
+    norm!(success_prelude_List_shifted_0, "prelude/List/shifted/0");
+    norm!(success_prelude_List_shifted_1, "prelude/List/shifted/1");
+    norm!(success_prelude_List_unzip_0, "prelude/List/unzip/0");
+    norm!(success_prelude_List_unzip_1, "prelude/List/unzip/1");
+    norm!(success_prelude_Natural_build_0, "prelude/Natural/build/0");
+    norm!(success_prelude_Natural_build_1, "prelude/Natural/build/1");
+    norm!(success_prelude_Natural_enumerate_0, "prelude/Natural/enumerate/0");
+    norm!(success_prelude_Natural_enumerate_1, "prelude/Natural/enumerate/1");
+    norm!(success_prelude_Natural_even_0, "prelude/Natural/even/0");
+    norm!(success_prelude_Natural_even_1, "prelude/Natural/even/1");
+    norm!(success_prelude_Natural_fold_0, "prelude/Natural/fold/0");
+    norm!(success_prelude_Natural_fold_1, "prelude/Natural/fold/1");
+    norm!(success_prelude_Natural_fold_2, "prelude/Natural/fold/2");
+    norm!(success_prelude_Natural_isZero_0, "prelude/Natural/isZero/0");
+    norm!(success_prelude_Natural_isZero_1, "prelude/Natural/isZero/1");
+    norm!(success_prelude_Natural_odd_0, "prelude/Natural/odd/0");
+    norm!(success_prelude_Natural_odd_1, "prelude/Natural/odd/1");
+    norm!(success_prelude_Natural_product_0, "prelude/Natural/product/0");
+    norm!(success_prelude_Natural_product_1, "prelude/Natural/product/1");
+    norm!(success_prelude_Natural_show_0, "prelude/Natural/show/0");
+    norm!(success_prelude_Natural_show_1, "prelude/Natural/show/1");
+    norm!(success_prelude_Natural_sum_0, "prelude/Natural/sum/0");
+    norm!(success_prelude_Natural_sum_1, "prelude/Natural/sum/1");
+    // norm!(success_prelude_Natural_toDouble_0, "prelude/Natural/toDouble/0");
+    // norm!(success_prelude_Natural_toDouble_1, "prelude/Natural/toDouble/1");
+    norm!(success_prelude_Natural_toInteger_0, "prelude/Natural/toInteger/0");
+    norm!(success_prelude_Natural_toInteger_1, "prelude/Natural/toInteger/1");
+    norm!(success_prelude_Optional_all_0, "prelude/Optional/all/0");
+    norm!(success_prelude_Optional_all_1, "prelude/Optional/all/1");
+    norm!(success_prelude_Optional_any_0, "prelude/Optional/any/0");
+    norm!(success_prelude_Optional_any_1, "prelude/Optional/any/1");
+    norm!(success_prelude_Optional_build_0, "prelude/Optional/build/0");
+    norm!(success_prelude_Optional_build_1, "prelude/Optional/build/1");
+    norm!(success_prelude_Optional_concat_0, "prelude/Optional/concat/0");
+    norm!(success_prelude_Optional_concat_1, "prelude/Optional/concat/1");
+    norm!(success_prelude_Optional_concat_2, "prelude/Optional/concat/2");
+    norm!(success_prelude_Optional_filter_0, "prelude/Optional/filter/0");
+    norm!(success_prelude_Optional_filter_1, "prelude/Optional/filter/1");
+    norm!(success_prelude_Optional_fold_0, "prelude/Optional/fold/0");
+    norm!(success_prelude_Optional_fold_1, "prelude/Optional/fold/1");
+    norm!(success_prelude_Optional_head_0, "prelude/Optional/head/0");
+    norm!(success_prelude_Optional_head_1, "prelude/Optional/head/1");
+    norm!(success_prelude_Optional_head_2, "prelude/Optional/head/2");
+    norm!(success_prelude_Optional_last_0, "prelude/Optional/last/0");
+    norm!(success_prelude_Optional_last_1, "prelude/Optional/last/1");
+    norm!(success_prelude_Optional_last_2, "prelude/Optional/last/2");
+    norm!(success_prelude_Optional_length_0, "prelude/Optional/length/0");
+    norm!(success_prelude_Optional_length_1, "prelude/Optional/length/1");
+    norm!(success_prelude_Optional_map_0, "prelude/Optional/map/0");
+    norm!(success_prelude_Optional_map_1, "prelude/Optional/map/1");
+    norm!(success_prelude_Optional_null_0, "prelude/Optional/null/0");
+    norm!(success_prelude_Optional_null_1, "prelude/Optional/null/1");
+    norm!(success_prelude_Optional_toList_0, "prelude/Optional/toList/0");
+    norm!(success_prelude_Optional_toList_1, "prelude/Optional/toList/1");
+    norm!(success_prelude_Optional_unzip_0, "prelude/Optional/unzip/0");
+    norm!(success_prelude_Optional_unzip_1, "prelude/Optional/unzip/1");
+    norm!(success_prelude_Text_concat_0, "prelude/Text/concat/0");
+    norm!(success_prelude_Text_concat_1, "prelude/Text/concat/1");
+    norm!(success_prelude_Text_concatMap_0, "prelude/Text/concatMap/0");
+    norm!(success_prelude_Text_concatMap_1, "prelude/Text/concatMap/1");
+    // norm!(success_prelude_Text_concatMapSep_0, "prelude/Text/concatMapSep/0");
+    // norm!(success_prelude_Text_concatMapSep_1, "prelude/Text/concatMapSep/1");
+    // norm!(success_prelude_Text_concatSep_0, "prelude/Text/concatSep/0");
+    // norm!(success_prelude_Text_concatSep_1, "prelude/Text/concatSep/1");
+    // norm!(success_prelude_Text_show_0, "prelude/Text/show/0");
+    // norm!(success_prelude_Text_show_1, "prelude/Text/show/1");
+    // norm!(success_remoteSystems, "remoteSystems");
+
+    // norm!(success_simple_doubleShow, "simple/doubleShow");
+    norm!(success_simple_enum, "simple/enum");
+    // norm!(success_simple_integerShow, "simple/integerShow");
+    // norm!(success_simple_integerToDouble, "simple/integerToDouble");
+    norm!(success_simple_letlet, "simple/letlet");
+    norm!(success_simple_listBuild, "simple/listBuild");
+    norm!(success_simple_multiLine, "simple/multiLine");
+    norm!(success_simple_naturalBuild, "simple/naturalBuild");
+    norm!(success_simple_naturalPlus, "simple/naturalPlus");
+    norm!(success_simple_naturalShow, "simple/naturalShow");
+    norm!(success_simple_naturalToInteger, "simple/naturalToInteger");
+    norm!(success_simple_optionalBuild, "simple/optionalBuild");
+    norm!(success_simple_optionalBuildFold, "simple/optionalBuildFold");
+    norm!(success_simple_optionalFold, "simple/optionalFold");
+    // norm!(success_simple_sortOperator, "simple/sortOperator");
+    norm!(success_simplifications_and, "simplifications/and");
+    norm!(success_simplifications_eq, "simplifications/eq");
+    norm!(success_simplifications_ifThenElse, "simplifications/ifThenElse");
+    norm!(success_simplifications_ne, "simplifications/ne");
+    norm!(success_simplifications_or, "simplifications/or");
+
+    norm!(success_unit_Bool, "unit/Bool");
+    norm!(success_unit_Double, "unit/Double");
+    norm!(success_unit_DoubleLiteral, "unit/DoubleLiteral");
+    norm!(success_unit_DoubleShow, "unit/DoubleShow");
+    // norm!(success_unit_DoubleShowValue, "unit/DoubleShowValue");
+    norm!(success_unit_EmptyAlternative, "unit/EmptyAlternative");
+    norm!(success_unit_FunctionApplicationCapture, "unit/FunctionApplicationCapture");
+    norm!(success_unit_FunctionApplicationNoSubstitute, "unit/FunctionApplicationNoSubstitute");
+    norm!(success_unit_FunctionApplicationNormalizeArguments, "unit/FunctionApplicationNormalizeArguments");
+    norm!(success_unit_FunctionApplicationSubstitute, "unit/FunctionApplicationSubstitute");
+    norm!(success_unit_FunctionNormalizeArguments, "unit/FunctionNormalizeArguments");
+    norm!(success_unit_FunctionTypeNormalizeArguments, "unit/FunctionTypeNormalizeArguments");
+    norm!(success_unit_IfAlternativesIdentical, "unit/IfAlternativesIdentical");
+    norm!(success_unit_IfFalse, "unit/IfFalse");
+    norm!(success_unit_IfNormalizePredicateAndBranches, "unit/IfNormalizePredicateAndBranches");
+    norm!(success_unit_IfTrivial, "unit/IfTrivial");
+    norm!(success_unit_IfTrue, "unit/IfTrue");
+    norm!(success_unit_Integer, "unit/Integer");
+    norm!(success_unit_IntegerNegative, "unit/IntegerNegative");
+    norm!(success_unit_IntegerPositive, "unit/IntegerPositive");
+    // norm!(success_unit_IntegerShow_12, "unit/IntegerShow-12");
+    // norm!(success_unit_IntegerShow12, "unit/IntegerShow12");
+    norm!(success_unit_IntegerShow, "unit/IntegerShow");
+    // norm!(success_unit_IntegerToDouble_12, "unit/IntegerToDouble-12");
+    // norm!(success_unit_IntegerToDouble12, "unit/IntegerToDouble12");
+    norm!(success_unit_IntegerToDouble, "unit/IntegerToDouble");
+    norm!(success_unit_Kind, "unit/Kind");
+    norm!(success_unit_Let, "unit/Let");
+    norm!(success_unit_LetWithType, "unit/LetWithType");
+    norm!(success_unit_List, "unit/List");
+    norm!(success_unit_ListBuild, "unit/ListBuild");
+    norm!(success_unit_ListBuildFoldFusion, "unit/ListBuildFoldFusion");
+    norm!(success_unit_ListBuildImplementation, "unit/ListBuildImplementation");
+    norm!(success_unit_ListFold, "unit/ListFold");
+    norm!(success_unit_ListFoldEmpty, "unit/ListFoldEmpty");
+    norm!(success_unit_ListFoldOne, "unit/ListFoldOne");
+    norm!(success_unit_ListHead, "unit/ListHead");
+    norm!(success_unit_ListHeadEmpty, "unit/ListHeadEmpty");
+    norm!(success_unit_ListHeadOne, "unit/ListHeadOne");
+    norm!(success_unit_ListIndexed, "unit/ListIndexed");
+    norm!(success_unit_ListIndexedEmpty, "unit/ListIndexedEmpty");
+    norm!(success_unit_ListIndexedOne, "unit/ListIndexedOne");
+    norm!(success_unit_ListLast, "unit/ListLast");
+    norm!(success_unit_ListLastEmpty, "unit/ListLastEmpty");
+    norm!(success_unit_ListLastOne, "unit/ListLastOne");
+    norm!(success_unit_ListLength, "unit/ListLength");
+    norm!(success_unit_ListLengthEmpty, "unit/ListLengthEmpty");
+    norm!(success_unit_ListLengthOne, "unit/ListLengthOne");
+    norm!(success_unit_ListNormalizeElements, "unit/ListNormalizeElements");
+    norm!(success_unit_ListNormalizeTypeAnnotation, "unit/ListNormalizeTypeAnnotation");
+    norm!(success_unit_ListReverse, "unit/ListReverse");
+    norm!(success_unit_ListReverseEmpty, "unit/ListReverseEmpty");
+    norm!(success_unit_ListReverseTwo, "unit/ListReverseTwo");
+    norm!(success_unit_Merge, "unit/Merge");
+    norm!(success_unit_MergeEmptyAlternative, "unit/MergeEmptyAlternative");
+    norm!(success_unit_MergeNormalizeArguments, "unit/MergeNormalizeArguments");
+    norm!(success_unit_MergeWithType, "unit/MergeWithType");
+    norm!(success_unit_MergeWithTypeNormalizeArguments, "unit/MergeWithTypeNormalizeArguments");
+    norm!(success_unit_Natural, "unit/Natural");
+    norm!(success_unit_NaturalBuild, "unit/NaturalBuild");
+    norm!(success_unit_NaturalBuildFoldFusion, "unit/NaturalBuildFoldFusion");
+    norm!(success_unit_NaturalBuildImplementation, "unit/NaturalBuildImplementation");
+    norm!(success_unit_NaturalEven, "unit/NaturalEven");
+    norm!(success_unit_NaturalEvenOne, "unit/NaturalEvenOne");
+    norm!(success_unit_NaturalEvenZero, "unit/NaturalEvenZero");
+    norm!(success_unit_NaturalFold, "unit/NaturalFold");
+    norm!(success_unit_NaturalFoldOne, "unit/NaturalFoldOne");
+    norm!(success_unit_NaturalFoldZero, "unit/NaturalFoldZero");
+    norm!(success_unit_NaturalIsZero, "unit/NaturalIsZero");
+    norm!(success_unit_NaturalIsZeroOne, "unit/NaturalIsZeroOne");
+    norm!(success_unit_NaturalIsZeroZero, "unit/NaturalIsZeroZero");
+    norm!(success_unit_NaturalLiteral, "unit/NaturalLiteral");
+    norm!(success_unit_NaturalOdd, "unit/NaturalOdd");
+    norm!(success_unit_NaturalOddOne, "unit/NaturalOddOne");
+    norm!(success_unit_NaturalOddZero, "unit/NaturalOddZero");
+    norm!(success_unit_NaturalShow, "unit/NaturalShow");
+    norm!(success_unit_NaturalShowOne, "unit/NaturalShowOne");
+    norm!(success_unit_NaturalToInteger, "unit/NaturalToInteger");
+    norm!(success_unit_NaturalToIntegerOne, "unit/NaturalToIntegerOne");
+    norm!(success_unit_None, "unit/None");
+    norm!(success_unit_NoneNatural, "unit/NoneNatural");
+    norm!(success_unit_OperatorAndEquivalentArguments, "unit/OperatorAndEquivalentArguments");
+    norm!(success_unit_OperatorAndLhsFalse, "unit/OperatorAndLhsFalse");
+    norm!(success_unit_OperatorAndLhsTrue, "unit/OperatorAndLhsTrue");
+    norm!(success_unit_OperatorAndNormalizeArguments, "unit/OperatorAndNormalizeArguments");
+    norm!(success_unit_OperatorAndRhsFalse, "unit/OperatorAndRhsFalse");
+    norm!(success_unit_OperatorAndRhsTrue, "unit/OperatorAndRhsTrue");
+    norm!(success_unit_OperatorEqualEquivalentArguments, "unit/OperatorEqualEquivalentArguments");
+    norm!(success_unit_OperatorEqualLhsTrue, "unit/OperatorEqualLhsTrue");
+    norm!(success_unit_OperatorEqualNormalizeArguments, "unit/OperatorEqualNormalizeArguments");
+    norm!(success_unit_OperatorEqualRhsTrue, "unit/OperatorEqualRhsTrue");
+    norm!(success_unit_OperatorListConcatenateLhsEmpty, "unit/OperatorListConcatenateLhsEmpty");
+    norm!(success_unit_OperatorListConcatenateListList, "unit/OperatorListConcatenateListList");
+    norm!(success_unit_OperatorListConcatenateNormalizeArguments, "unit/OperatorListConcatenateNormalizeArguments");
+    norm!(success_unit_OperatorListConcatenateRhsEmpty, "unit/OperatorListConcatenateRhsEmpty");
+    norm!(success_unit_OperatorNotEqualEquivalentArguments, "unit/OperatorNotEqualEquivalentArguments");
+    norm!(success_unit_OperatorNotEqualLhsFalse, "unit/OperatorNotEqualLhsFalse");
+    norm!(success_unit_OperatorNotEqualNormalizeArguments, "unit/OperatorNotEqualNormalizeArguments");
+    norm!(success_unit_OperatorNotEqualRhsFalse, "unit/OperatorNotEqualRhsFalse");
+    norm!(success_unit_OperatorOrEquivalentArguments, "unit/OperatorOrEquivalentArguments");
+    norm!(success_unit_OperatorOrLhsFalse, "unit/OperatorOrLhsFalse");
+    norm!(success_unit_OperatorOrLhsTrue, "unit/OperatorOrLhsTrue");
+    norm!(success_unit_OperatorOrNormalizeArguments, "unit/OperatorOrNormalizeArguments");
+    norm!(success_unit_OperatorOrRhsFalse, "unit/OperatorOrRhsFalse");
+    norm!(success_unit_OperatorOrRhsTrue, "unit/OperatorOrRhsTrue");
+    norm!(success_unit_OperatorPlusLhsZero, "unit/OperatorPlusLhsZero");
+    norm!(success_unit_OperatorPlusNormalizeArguments, "unit/OperatorPlusNormalizeArguments");
+    norm!(success_unit_OperatorPlusOneAndOne, "unit/OperatorPlusOneAndOne");
+    norm!(success_unit_OperatorPlusRhsZero, "unit/OperatorPlusRhsZero");
+    norm!(success_unit_OperatorTextConcatenateLhsEmpty, "unit/OperatorTextConcatenateLhsEmpty");
+    norm!(success_unit_OperatorTextConcatenateLhsNonEmpty, "unit/OperatorTextConcatenateLhsNonEmpty");
+    norm!(success_unit_OperatorTextConcatenateTextText, "unit/OperatorTextConcatenateTextText");
+    norm!(success_unit_OperatorTimesLhsOne, "unit/OperatorTimesLhsOne");
+    norm!(success_unit_OperatorTimesLhsZero, "unit/OperatorTimesLhsZero");
+    norm!(success_unit_OperatorTimesNormalizeArguments, "unit/OperatorTimesNormalizeArguments");
+    norm!(success_unit_OperatorTimesRhsOne, "unit/OperatorTimesRhsOne");
+    norm!(success_unit_OperatorTimesRhsZero, "unit/OperatorTimesRhsZero");
+    norm!(success_unit_OperatorTimesTwoAndTwo, "unit/OperatorTimesTwoAndTwo");
+    norm!(success_unit_Optional, "unit/Optional");
+    norm!(success_unit_OptionalBuild, "unit/OptionalBuild");
+    norm!(success_unit_OptionalBuildFoldFusion, "unit/OptionalBuildFoldFusion");
+    norm!(success_unit_OptionalBuildImplementation, "unit/OptionalBuildImplementation");
+    norm!(success_unit_OptionalFold, "unit/OptionalFold");
+    norm!(success_unit_OptionalFoldNone, "unit/OptionalFoldNone");
+    norm!(success_unit_OptionalFoldSome, "unit/OptionalFoldSome");
+    norm!(success_unit_Record, "unit/Record");
+    norm!(success_unit_RecordEmpty, "unit/RecordEmpty");
+    norm!(success_unit_RecordProjection, "unit/RecordProjection");
+    norm!(success_unit_RecordProjectionEmpty, "unit/RecordProjectionEmpty");
+    norm!(success_unit_RecordProjectionNormalizeArguments, "unit/RecordProjectionNormalizeArguments");
+    norm!(success_unit_RecordSelection, "unit/RecordSelection");
+    norm!(success_unit_RecordSelectionNormalizeArguments, "unit/RecordSelectionNormalizeArguments");
+    norm!(success_unit_RecordType, "unit/RecordType");
+    norm!(success_unit_RecordTypeEmpty, "unit/RecordTypeEmpty");
+    // norm!(success_unit_RecursiveRecordMergeCollision, "unit/RecursiveRecordMergeCollision");
+    // norm!(success_unit_RecursiveRecordMergeLhsEmpty, "unit/RecursiveRecordMergeLhsEmpty");
+    // norm!(success_unit_RecursiveRecordMergeNoCollision, "unit/RecursiveRecordMergeNoCollision");
+    // norm!(success_unit_RecursiveRecordMergeNormalizeArguments, "unit/RecursiveRecordMergeNormalizeArguments");
+    // norm!(success_unit_RecursiveRecordMergeRhsEmpty, "unit/RecursiveRecordMergeRhsEmpty");
+    // norm!(success_unit_RecursiveRecordTypeMergeCollision, "unit/RecursiveRecordTypeMergeCollision");
+    // norm!(success_unit_RecursiveRecordTypeMergeLhsEmpty, "unit/RecursiveRecordTypeMergeLhsEmpty");
+    // norm!(success_unit_RecursiveRecordTypeMergeNoCollision, "unit/RecursiveRecordTypeMergeNoCollision");
+    // norm!(success_unit_RecursiveRecordTypeMergeNormalizeArguments, "unit/RecursiveRecordTypeMergeNormalizeArguments");
+    // norm!(success_unit_RecursiveRecordTypeMergeRhsEmpty, "unit/RecursiveRecordTypeMergeRhsEmpty");
+    // norm!(success_unit_RecursiveRecordTypeMergeSorts, "unit/RecursiveRecordTypeMergeSorts");
+    // norm!(success_unit_RightBiasedRecordMergeCollision, "unit/RightBiasedRecordMergeCollision");
+    // norm!(success_unit_RightBiasedRecordMergeLhsEmpty, "unit/RightBiasedRecordMergeLhsEmpty");
+    // norm!(success_unit_RightBiasedRecordMergeNoCollision, "unit/RightBiasedRecordMergeNoCollision");
+    // norm!(success_unit_RightBiasedRecordMergeNormalizeArguments, "unit/RightBiasedRecordMergeNormalizeArguments");
+    // norm!(success_unit_RightBiasedRecordMergeRhsEmpty, "unit/RightBiasedRecordMergeRhsEmpty");
+    norm!(success_unit_SomeNormalizeArguments, "unit/SomeNormalizeArguments");
+    norm!(success_unit_Sort, "unit/Sort");
+    norm!(success_unit_Text, "unit/Text");
+    norm!(success_unit_TextInterpolate, "unit/TextInterpolate");
+    norm!(success_unit_TextLiteral, "unit/TextLiteral");
+    norm!(success_unit_TextNormalizeInterpolations, "unit/TextNormalizeInterpolations");
+    norm!(success_unit_TextShow, "unit/TextShow");
+    // norm!(success_unit_TextShowAllEscapes, "unit/TextShowAllEscapes");
+    norm!(success_unit_True, "unit/True");
+    norm!(success_unit_Type, "unit/Type");
+    norm!(success_unit_TypeAnnotation, "unit/TypeAnnotation");
+    norm!(success_unit_UnionNormalizeAlternatives, "unit/UnionNormalizeAlternatives");
+    norm!(success_unit_UnionNormalizeArguments, "unit/UnionNormalizeArguments");
+    norm!(success_unit_UnionProjectConstructor, "unit/UnionProjectConstructor");
+    norm!(success_unit_UnionSortAlternatives, "unit/UnionSortAlternatives");
+    norm!(success_unit_UnionType, "unit/UnionType");
+    norm!(success_unit_UnionTypeEmpty, "unit/UnionTypeEmpty");
+    norm!(success_unit_UnionTypeNormalizeArguments, "unit/UnionTypeNormalizeArguments");
+    norm!(success_unit_Variable, "unit/Variable");
+
+    alpha_norm!(alpha_success_unit_FunctionBindingUnderscore, "unit/FunctionBindingUnderscore");
+    alpha_norm!(alpha_success_unit_FunctionBindingX, "unit/FunctionBindingX");
+    alpha_norm!(alpha_success_unit_FunctionNestedBindingX, "unit/FunctionNestedBindingX");
+    alpha_norm!(alpha_success_unit_FunctionTypeBindingUnderscore, "unit/FunctionTypeBindingUnderscore");
+    alpha_norm!(alpha_success_unit_FunctionTypeBindingX, "unit/FunctionTypeBindingX");
+    alpha_norm!(alpha_success_unit_FunctionTypeNestedBindingX, "unit/FunctionTypeNestedBindingX");
+}
-- 
cgit v1.2.3