s/ExprF/ExprKind/

12 files changed, 158 insertions, 150 deletions

diff --git a/dhall/src/semantics/core/value_kind.rs b/dhall/src/semantics/core/value_kind.rs
index 47df39d..35b2b23 100644
--- a/dhall/src/semantics/core/value_kind.rs
+++ b/dhall/src/semantics/core/value_kind.rs
@@ -5,7 +5,7 @@ use crate::semantics::core::var::{AlphaLabel, AlphaVar, Shift, Subst};
 use crate::semantics::phase::{Normalized, NormalizedExpr};
 use crate::semantics::to_expr;
 use crate::syntax::{
-    Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label,
+    Builtin, Const, ExprKind, Integer, InterpolatedTextContents, Label,
     NaiveDouble, Natural,
 };
 
@@ -43,7 +43,7 @@ pub(crate) enum ValueKind {
     TextLit(Vec<InterpolatedTextContents<Value>>),
     Equivalence(Value, Value),
     // Invariant: in whnf, this must not contain a value captured by one of the variants above.
-    PartialExpr(ExprF<Value, Normalized>),
+    PartialExpr(ExprKind<Value, Normalized>),
 }
 
 impl ValueKind {
diff --git a/dhall/src/semantics/core/var.rs b/dhall/src/semantics/core/var.rs
index 77473f6..1548713 100644
--- a/dhall/src/semantics/core/var.rs
+++ b/dhall/src/semantics/core/var.rs
@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 
-use crate::syntax::{ExprF, InterpolatedTextContents, Label, V};
+use crate::syntax::{ExprKind, InterpolatedTextContents, Label, V};
 
 /// Stores a pair of variables: a normal one and one
 /// that corresponds to the alpha-normalized version of the first one.
@@ -190,7 +190,7 @@ impl<T: Shift> Shift for std::cell::RefCell<T> {
     }
 }
 
-impl<T: Shift, E: Clone> Shift for ExprF<T, E> {
+impl<T: Shift, E: Clone> Shift for ExprKind<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)?),
@@ -262,7 +262,7 @@ impl<S, T: Subst<S>> Subst<S> for std::cell::RefCell<T> {
     }
 }
 
-impl<S: Shift, T: Subst<S>, E: Clone> Subst<S> for ExprF<T, E> {
+impl<S: Shift, T: Subst<S>, E: Clone> Subst<S> for ExprKind<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),
diff --git a/dhall/src/semantics/phase/normalize.rs b/dhall/src/semantics/phase/normalize.rs
index 157d1f3..3e612aa 100644
--- a/dhall/src/semantics/phase/normalize.rs
+++ b/dhall/src/semantics/phase/normalize.rs
@@ -7,8 +7,8 @@ use crate::semantics::phase::Normalized;
 use crate::syntax;
 use crate::syntax::Const::Type;
 use crate::syntax::{
-    BinOp, Builtin, ExprF, InterpolatedText, InterpolatedTextContents, Label,
-    NaiveDouble,
+    BinOp, Builtin, ExprKind, InterpolatedText, InterpolatedTextContents,
+    Label, NaiveDouble,
 };
 
 // Ad-hoc macro to help construct closures
@@ -46,7 +46,7 @@ macro_rules! make_closure {
         ValueKind::NEOptionalLit(v).into_value_with_type(opt_v_type)
     }};
     (1 + $($rest:tt)*) => {
-        ValueKind::PartialExpr(ExprF::BinOp(
+        ValueKind::PartialExpr(ExprKind::BinOp(
             syntax::BinOp::NaturalPlus,
             make_closure!($($rest)*),
             Value::from_kind_and_type(
@@ -61,7 +61,7 @@ macro_rules! make_closure {
         let head = make_closure!($($head)*);
         let tail = make_closure!($($tail)*);
         let list_type = tail.get_type_not_sort();
-        ValueKind::PartialExpr(ExprF::BinOp(
+        ValueKind::PartialExpr(ExprKind::BinOp(
             syntax::BinOp::ListAppend,
             ValueKind::NEListLit(vec![head])
                 .into_value_with_type(list_type.clone()),
@@ -404,7 +404,7 @@ pub(crate) fn apply_any(f: Value, a: Value, ty: &Value) -> ValueKind {
         }
         _ => {
             drop(f_borrow);
-            ValueKind::PartialExpr(ExprF::App(f, a))
+            ValueKind::PartialExpr(ExprKind::App(f, a))
         }
     }
 }
@@ -482,7 +482,7 @@ enum Ret<'a> {
     ValueKind(ValueKind),
     Value(Value),
     ValueRef(&'a Value),
-    Expr(ExprF<Value, Normalized>),
+    Expr(ExprKind<Value, Normalized>),
 }
 
 fn apply_binop<'a>(
@@ -590,7 +590,7 @@ fn apply_binop<'a>(
             };
             let kvs = merge_maps::<_, _, _, !>(kvs1, kvs2, |k, v1, v2| {
                 Ok(Value::from_kind_and_type(
-                    ValueKind::PartialExpr(ExprF::BinOp(
+                    ValueKind::PartialExpr(ExprKind::BinOp(
                         RecursiveRecordMerge,
                         v1.clone(),
                         v2.clone(),
@@ -610,7 +610,7 @@ fn apply_binop<'a>(
 }
 
 pub(crate) fn normalize_one_layer(
-    expr: ExprF<Value, Normalized>,
+    expr: ExprKind<Value, Normalized>,
     ty: &Value,
 ) -> ValueKind {
     use ValueKind::{
@@ -620,31 +620,31 @@ pub(crate) fn normalize_one_layer(
     };
 
     let ret = match expr {
-        ExprF::Import(_) => unreachable!(
+        ExprKind::Import(_) => unreachable!(
             "There should remain no imports in a resolved expression"
         ),
         // Those cases have already been completely handled in the typechecking phase (using
         // `RetWhole`), so they won't appear here.
-        ExprF::Lam(_, _, _)
-        | ExprF::Pi(_, _, _)
-        | ExprF::Let(_, _, _, _)
-        | ExprF::Embed(_)
-        | ExprF::Const(_)
-        | ExprF::Builtin(_)
-        | ExprF::Var(_)
-        | ExprF::Annot(_, _)
-        | ExprF::RecordType(_)
-        | ExprF::UnionType(_) => {
+        ExprKind::Lam(_, _, _)
+        | ExprKind::Pi(_, _, _)
+        | ExprKind::Let(_, _, _, _)
+        | ExprKind::Embed(_)
+        | ExprKind::Const(_)
+        | ExprKind::Builtin(_)
+        | ExprKind::Var(_)
+        | ExprKind::Annot(_, _)
+        | ExprKind::RecordType(_)
+        | ExprKind::UnionType(_) => {
             unreachable!("This case should have been handled in typecheck")
         }
-        ExprF::Assert(_) => Ret::Expr(expr),
-        ExprF::App(v, a) => Ret::Value(v.app(a)),
-        ExprF::BoolLit(b) => Ret::ValueKind(BoolLit(b)),
-        ExprF::NaturalLit(n) => Ret::ValueKind(NaturalLit(n)),
-        ExprF::IntegerLit(n) => Ret::ValueKind(IntegerLit(n)),
-        ExprF::DoubleLit(n) => Ret::ValueKind(DoubleLit(n)),
-        ExprF::SomeLit(e) => Ret::ValueKind(NEOptionalLit(e)),
-        ExprF::EmptyListLit(ref t) => {
+        ExprKind::Assert(_) => Ret::Expr(expr),
+        ExprKind::App(v, a) => Ret::Value(v.app(a)),
+        ExprKind::BoolLit(b) => Ret::ValueKind(BoolLit(b)),
+        ExprKind::NaturalLit(n) => Ret::ValueKind(NaturalLit(n)),
+        ExprKind::IntegerLit(n) => Ret::ValueKind(IntegerLit(n)),
+        ExprKind::DoubleLit(n) => Ret::ValueKind(DoubleLit(n)),
+        ExprKind::SomeLit(e) => Ret::ValueKind(NEOptionalLit(e)),
+        ExprKind::EmptyListLit(ref t) => {
             // Check if the type is of the form `List x`
             let t_borrow = t.as_whnf();
             match &*t_borrow {
@@ -657,13 +657,13 @@ pub(crate) fn normalize_one_layer(
                 }
             }
         }
-        ExprF::NEListLit(elts) => {
+        ExprKind::NEListLit(elts) => {
             Ret::ValueKind(NEListLit(elts.into_iter().collect()))
         }
-        ExprF::RecordLit(kvs) => {
+        ExprKind::RecordLit(kvs) => {
             Ret::ValueKind(RecordLit(kvs.into_iter().collect()))
         }
-        ExprF::TextLit(elts) => {
+        ExprKind::TextLit(elts) => {
             use InterpolatedTextContents::Expr;
             let elts: Vec<_> = squash_textlit(elts.into_iter());
             // Simplify bare interpolation
@@ -673,7 +673,7 @@ pub(crate) fn normalize_one_layer(
                 Ret::ValueKind(TextLit(elts))
             }
         }
-        ExprF::BoolIf(ref b, ref e1, ref e2) => {
+        ExprKind::BoolIf(ref b, ref e1, ref e2) => {
             let b_borrow = b.as_whnf();
             match &*b_borrow {
                 BoolLit(true) => Ret::ValueRef(e1),
@@ -695,15 +695,15 @@ pub(crate) fn normalize_one_layer(
                 }
             }
         }
-        ExprF::BinOp(o, ref x, ref y) => match apply_binop(o, x, y, ty) {
+        ExprKind::BinOp(o, ref x, ref y) => match apply_binop(o, x, y, ty) {
             Some(ret) => ret,
             None => Ret::Expr(expr),
         },
 
-        ExprF::Projection(_, ref ls) if ls.is_empty() => {
+        ExprKind::Projection(_, ref ls) if ls.is_empty() => {
             Ret::ValueKind(RecordLit(HashMap::new()))
         }
-        ExprF::Projection(ref v, ref ls) => {
+        ExprKind::Projection(ref v, ref ls) => {
             let v_borrow = v.as_whnf();
             match &*v_borrow {
                 RecordLit(kvs) => Ret::ValueKind(RecordLit(
@@ -719,7 +719,7 @@ pub(crate) fn normalize_one_layer(
                 }
             }
         }
-        ExprF::Field(ref v, ref l) => {
+        ExprKind::Field(ref v, ref l) => {
             let v_borrow = v.as_whnf();
             match &*v_borrow {
                 RecordLit(kvs) => match kvs.get(l) {
@@ -738,11 +738,11 @@ pub(crate) fn normalize_one_layer(
                 }
             }
         }
-        ExprF::ProjectionByExpr(_, _) => {
+        ExprKind::ProjectionByExpr(_, _) => {
             unimplemented!("selection by expression")
         }
 
-        ExprF::Merge(ref handlers, ref variant, _) => {
+        ExprKind::Merge(ref handlers, ref variant, _) => {
             let handlers_borrow = handlers.as_whnf();
             let variant_borrow = variant.as_whnf();
             match (&*handlers_borrow, &*variant_borrow) {
@@ -769,7 +769,7 @@ pub(crate) fn normalize_one_layer(
                 }
             }
         }
-        ExprF::ToMap(_, _) => unimplemented!("toMap"),
+        ExprKind::ToMap(_, _) => unimplemented!("toMap"),
     };
 
     match ret {
diff --git a/dhall/src/semantics/phase/typecheck.rs b/dhall/src/semantics/phase/typecheck.rs
index 5041235..f83bb94 100644
--- a/dhall/src/semantics/phase/typecheck.rs
+++ b/dhall/src/semantics/phase/typecheck.rs
@@ -10,7 +10,8 @@ use crate::semantics::phase::normalize::merge_maps;
 use crate::semantics::phase::Normalized;
 use crate::syntax;
 use crate::syntax::{
-    Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label, RawExpr, Span,
+    Builtin, Const, Expr, ExprKind, InterpolatedTextContents, Label, RawExpr,
+    Span,
 };
 
 fn tck_pi_type(
@@ -149,24 +150,24 @@ pub fn rc<E>(x: RawExpr<E>) -> Expr<E> {
 
 // Ad-hoc macro to help construct the types of builtins
 macro_rules! make_type {
-    (Type) => { ExprF::Const(Const::Type) };
-    (Bool) => { ExprF::Builtin(Builtin::Bool) };
-    (Natural) => { ExprF::Builtin(Builtin::Natural) };
-    (Integer) => { ExprF::Builtin(Builtin::Integer) };
-    (Double) => { ExprF::Builtin(Builtin::Double) };
-    (Text) => { ExprF::Builtin(Builtin::Text) };
+    (Type) => { ExprKind::Const(Const::Type) };
+    (Bool) => { ExprKind::Builtin(Builtin::Bool) };
+    (Natural) => { ExprKind::Builtin(Builtin::Natural) };
+    (Integer) => { ExprKind::Builtin(Builtin::Integer) };
+    (Double) => { ExprKind::Builtin(Builtin::Double) };
+    (Text) => { ExprKind::Builtin(Builtin::Text) };
     ($var:ident) => {
-        ExprF::Var(syntax::V(stringify!($var).into(), 0))
+        ExprKind::Var(syntax::V(stringify!($var).into(), 0))
     };
     (Optional $ty:ident) => {
-        ExprF::App(
-            rc(ExprF::Builtin(Builtin::Optional)),
+        ExprKind::App(
+            rc(ExprKind::Builtin(Builtin::Optional)),
             rc(make_type!($ty))
         )
     };
     (List $($rest:tt)*) => {
-        ExprF::App(
-            rc(ExprF::Builtin(Builtin::List)),
+        ExprKind::App(
+            rc(ExprKind::Builtin(Builtin::List)),
             rc(make_type!($($rest)*))
         )
     };
@@ -178,24 +179,24 @@ macro_rules! make_type {
                 rc(make_type!($ty)),
             );
         )*
-        ExprF::RecordType(kts)
+        ExprKind::RecordType(kts)
     }};
     ($ty:ident -> $($rest:tt)*) => {
-        ExprF::Pi(
+        ExprKind::Pi(
             "_".into(),
             rc(make_type!($ty)),
             rc(make_type!($($rest)*))
         )
     };
     (($($arg:tt)*) -> $($rest:tt)*) => {
-        ExprF::Pi(
+        ExprKind::Pi(
             "_".into(),
             rc(make_type!($($arg)*)),
             rc(make_type!($($rest)*))
         )
     };
     (forall ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => {
-        ExprF::Pi(
+        ExprKind::Pi(
             stringify!($var).into(),
             rc(make_type!($($ty)*)),
             rc(make_type!($($rest)*))
@@ -304,7 +305,7 @@ fn type_with(
     ctx: &TypecheckContext,
     e: Expr<Normalized>,
 ) -> Result<Value, TypeError> {
-    use syntax::ExprF::{Annot, Embed, Lam, Let, Pi, Var};
+    use syntax::ExprKind::{Annot, Embed, Lam, Let, Pi, Var};
     let span = e.span();
 
     Ok(match e.as_ref() {
@@ -359,13 +360,13 @@ fn type_with(
 /// layer.
 fn type_last_layer(
     ctx: &TypecheckContext,
-    e: ExprF<Value, Normalized>,
+    e: ExprKind<Value, Normalized>,
     span: Span,
 ) -> Result<Value, TypeError> {
     use syntax::BinOp::*;
     use syntax::Builtin::*;
     use syntax::Const::Type;
-    use syntax::ExprF::*;
+    use syntax::ExprKind::*;
     use TypeMessage::*;
     let mkerr = |msg: TypeMessage| Err(TypeError::new(ctx, msg));
 
@@ -578,7 +579,7 @@ fn type_last_layer(
         }
         BinOp(RecursiveRecordMerge, l, r) => RetTypeOnly(type_last_layer(
             ctx,
-            ExprF::BinOp(
+            ExprKind::BinOp(
                 RecursiveRecordTypeMerge,
                 l.get_type()?,
                 r.get_type()?,
@@ -612,7 +613,7 @@ fn type_last_layer(
                 |_, l: &Value, r: &Value| {
                     type_last_layer(
                         ctx,
-                        ExprF::BinOp(
+                        ExprKind::BinOp(
                             RecursiveRecordTypeMerge,
                             l.clone(),
                             r.clone(),
@@ -806,5 +807,5 @@ pub(crate) fn typecheck_with(
     expr: Expr<Normalized>,
     ty: Expr<Normalized>,
 ) -> Result<Value, TypeError> {
-    typecheck(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
+    typecheck(expr.rewrap(ExprKind::Annot(expr.clone(), ty)))
 }
diff --git a/dhall/src/semantics/to_expr.rs b/dhall/src/semantics/to_expr.rs
index 74bd2fe..6099976 100644
--- a/dhall/src/semantics/to_expr.rs
+++ b/dhall/src/semantics/to_expr.rs
@@ -3,7 +3,7 @@ use crate::semantics::core::value_kind::ValueKind;
 use crate::semantics::phase::typecheck::rc;
 use crate::semantics::phase::NormalizedExpr;
 use crate::syntax;
-use crate::syntax::{Builtin, ExprF};
+use crate::syntax::{Builtin, ExprKind};
 
 #[derive(Copy, Clone)]
 /// Controls conversion from `Value` to `Expr`
@@ -31,7 +31,7 @@ pub(crate) fn kind_to_expr(
     opts: ToExprOptions,
 ) -> NormalizedExpr {
     match kind {
-        ValueKind::Lam(x, t, e) => rc(ExprF::Lam(
+        ValueKind::Lam(x, t, e) => rc(ExprKind::Lam(
             x.to_label_maybe_alpha(opts.alpha),
             t.to_expr(opts),
             e.to_expr(opts),
@@ -39,59 +39,63 @@ pub(crate) fn kind_to_expr(
         ValueKind::AppliedBuiltin(b, args) => args
             .iter()
             .map(|v| v.to_expr(opts))
-            .fold(rc(ExprF::Builtin(*b)), |acc, v| rc(ExprF::App(acc, v))),
-        ValueKind::Pi(x, t, e) => rc(ExprF::Pi(
+            .fold(rc(ExprKind::Builtin(*b)), |acc, v| {
+                rc(ExprKind::App(acc, v))
+            }),
+        ValueKind::Pi(x, t, e) => rc(ExprKind::Pi(
             x.to_label_maybe_alpha(opts.alpha),
             t.to_expr(opts),
             e.to_expr(opts),
         )),
-        ValueKind::Var(v) => rc(ExprF::Var(v.to_var(opts.alpha))),
-        ValueKind::Const(c) => rc(ExprF::Const(*c)),
-        ValueKind::BoolLit(b) => rc(ExprF::BoolLit(*b)),
-        ValueKind::NaturalLit(n) => rc(ExprF::NaturalLit(*n)),
-        ValueKind::IntegerLit(n) => rc(ExprF::IntegerLit(*n)),
-        ValueKind::DoubleLit(n) => rc(ExprF::DoubleLit(*n)),
-        ValueKind::EmptyOptionalLit(n) => rc(ExprF::App(
-            rc(ExprF::Builtin(Builtin::OptionalNone)),
+        ValueKind::Var(v) => rc(ExprKind::Var(v.to_var(opts.alpha))),
+        ValueKind::Const(c) => rc(ExprKind::Const(*c)),
+        ValueKind::BoolLit(b) => rc(ExprKind::BoolLit(*b)),
+        ValueKind::NaturalLit(n) => rc(ExprKind::NaturalLit(*n)),
+        ValueKind::IntegerLit(n) => rc(ExprKind::IntegerLit(*n)),
+        ValueKind::DoubleLit(n) => rc(ExprKind::DoubleLit(*n)),
+        ValueKind::EmptyOptionalLit(n) => rc(ExprKind::App(
+            rc(ExprKind::Builtin(Builtin::OptionalNone)),
             n.to_expr(opts),
         )),
-        ValueKind::NEOptionalLit(n) => rc(ExprF::SomeLit(n.to_expr(opts))),
-        ValueKind::EmptyListLit(n) => rc(ExprF::EmptyListLit(rc(ExprF::App(
-            rc(ExprF::Builtin(Builtin::List)),
-            n.to_expr(opts),
-        )))),
-        ValueKind::NEListLit(elts) => rc(ExprF::NEListLit(
+        ValueKind::NEOptionalLit(n) => rc(ExprKind::SomeLit(n.to_expr(opts))),
+        ValueKind::EmptyListLit(n) => {
+            rc(ExprKind::EmptyListLit(rc(ExprKind::App(
+                rc(ExprKind::Builtin(Builtin::List)),
+                n.to_expr(opts),
+            ))))
+        }
+        ValueKind::NEListLit(elts) => rc(ExprKind::NEListLit(
             elts.iter().map(|n| n.to_expr(opts)).collect(),
         )),
-        ValueKind::RecordLit(kvs) => rc(ExprF::RecordLit(
+        ValueKind::RecordLit(kvs) => rc(ExprKind::RecordLit(
             kvs.iter()
                 .map(|(k, v)| (k.clone(), v.to_expr(opts)))
                 .collect(),
         )),
-        ValueKind::RecordType(kts) => rc(ExprF::RecordType(
+        ValueKind::RecordType(kts) => rc(ExprKind::RecordType(
             kts.iter()
                 .map(|(k, v)| (k.clone(), v.to_expr(opts)))
                 .collect(),
         )),
-        ValueKind::UnionType(kts) => rc(ExprF::UnionType(
+        ValueKind::UnionType(kts) => rc(ExprKind::UnionType(
             kts.iter()
                 .map(|(k, v)| (k.clone(), v.as_ref().map(|v| v.to_expr(opts))))
                 .collect(),
         )),
-        ValueKind::UnionConstructor(l, kts) => rc(ExprF::Field(
+        ValueKind::UnionConstructor(l, kts) => rc(ExprKind::Field(
             ValueKind::UnionType(kts.clone()).to_expr(opts),
             l.clone(),
         )),
-        ValueKind::UnionLit(l, v, kts) => rc(ExprF::App(
+        ValueKind::UnionLit(l, v, kts) => rc(ExprKind::App(
             ValueKind::UnionConstructor(l.clone(), kts.clone()).to_expr(opts),
             v.to_expr(opts),
         )),
-        ValueKind::TextLit(elts) => rc(ExprF::TextLit(
+        ValueKind::TextLit(elts) => rc(ExprKind::TextLit(
             elts.iter()
                 .map(|contents| contents.map_ref(|e| e.to_expr(opts)))
                 .collect(),
         )),
-        ValueKind::Equivalence(x, y) => rc(ExprF::BinOp(
+        ValueKind::Equivalence(x, y) => rc(ExprKind::BinOp(
             syntax::BinOp::Equivalence,
             x.to_expr(opts),
             y.to_expr(opts),
diff --git a/dhall/src/syntax/ast/expr.rs b/dhall/src/syntax/ast/expr.rs
index 5b9f401..7ac342d 100644
--- a/dhall/src/syntax/ast/expr.rs
+++ b/dhall/src/syntax/ast/expr.rs
@@ -1,5 +1,5 @@
 use crate::syntax::map::{DupTreeMap, DupTreeSet};
-use crate::syntax::visitor::{self, ExprFMutVisitor, ExprFVisitor};
+use crate::syntax::visitor::{self, ExprKindMutVisitor, ExprKindVisitor};
 use crate::syntax::*;
 
 pub type Integer = isize;
@@ -144,7 +144,7 @@ pub enum Builtin {
 #[derive(Debug, Clone)]
 pub struct Expr<Embed>(Box<(RawExpr<Embed>, Span)>);
 
-pub type RawExpr<Embed> = ExprF<Expr<Embed>, Embed>;
+pub type RawExpr<Embed> = ExprKind<Expr<Embed>, Embed>;
 
 impl<Embed: PartialEq> std::cmp::PartialEq for Expr<Embed> {
     fn eq(&self, other: &Self) -> bool {
@@ -168,7 +168,7 @@ impl<Embed: std::hash::Hash> std::hash::Hash for Expr<Embed> {
 // much more generic code and improves pattern-matching behind
 // smart pointers.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub enum ExprF<SubExpr, Embed> {
+pub enum ExprKind<SubExpr, Embed> {
     Const(Const),
     ///  `x`
     ///  `x@n`
@@ -231,12 +231,12 @@ pub enum ExprF<SubExpr, Embed> {
     Embed(Embed),
 }
 
-impl<SE, E> ExprF<SE, E> {
+impl<SE, E> ExprKind<SE, E> {
     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>,
-    ) -> Result<ExprF<SE2, E>, Err>
+    ) -> Result<ExprKind<SE2, E>, Err>
     where
         E: Clone,
     {
@@ -250,7 +250,7 @@ impl<SE, E> ExprF<SE, E> {
     fn traverse_ref<'a, SE2, Err>(
         &'a self,
         visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
-    ) -> Result<ExprF<SE2, E>, Err>
+    ) -> Result<ExprKind<SE2, E>, Err>
     where
         E: Clone,
     {
@@ -268,7 +268,7 @@ impl<SE, E> ExprF<SE, E> {
         &'a self,
         mut map_subexpr: impl FnMut(&'a SE) -> SE2,
         mut map_under_binder: impl FnMut(&'a Label, &'a SE) -> SE2,
-    ) -> ExprF<SE2, E>
+    ) -> ExprKind<SE2, E>
     where
         E: Clone,
     {
@@ -281,7 +281,7 @@ impl<SE, E> ExprF<SE, E> {
     pub fn map_ref<'a, SE2>(
         &'a self,
         mut map_subexpr: impl FnMut(&'a SE) -> SE2,
-    ) -> ExprF<SE2, E>
+    ) -> ExprKind<SE2, E>
     where
         E: Clone,
     {
@@ -321,8 +321,8 @@ impl<E> Expr<E> {
         F1: FnMut(Import<Expr<E>>) -> Result<E, Err>,
     {
         match self.as_mut() {
-            ExprF::BinOp(BinOp::ImportAlt, l, r) => {
-                let garbage_expr = ExprF::BoolLit(false);
+            ExprKind::BinOp(BinOp::ImportAlt, l, r) => {
+                let garbage_expr = ExprKind::BoolLit(false);
                 let new_self = if l.traverse_resolve_mut(f).is_ok() {
                     l
                 } else {
@@ -334,7 +334,7 @@ impl<E> Expr<E> {
             }
             _ => {
                 self.as_mut().traverse_mut(|e| e.traverse_resolve_mut(f))?;
-                if let ExprF::Import(import) = self.as_mut() {
+                if let ExprKind::Import(import) = self.as_mut() {
                     let garbage_import = Import {
                         mode: ImportMode::Code,
                         location: ImportLocation::Missing,
@@ -342,7 +342,7 @@ impl<E> Expr<E> {
                     };
                     // Move out of &mut import
                     let import = std::mem::replace(import, garbage_import);
-                    *self.as_mut() = ExprF::Embed(f(import)?);
+                    *self.as_mut() = ExprKind::Embed(f(import)?);
                 }
             }
         }
diff --git a/dhall/src/syntax/ast/visitor.rs b/dhall/src/syntax/ast/visitor.rs
index b76d037..b557995 100644
--- a/dhall/src/syntax/ast/visitor.rs
+++ b/dhall/src/syntax/ast/visitor.rs
@@ -1,7 +1,7 @@
 use crate::syntax::*;
 use std::iter::FromIterator;
 
-/// A visitor trait that can be used to traverse `ExprF`s. We need this pattern so that Rust lets
+/// A visitor trait that can be used to traverse `ExprKind`s. We need this pattern so that Rust lets
 /// us have as much mutability as we can.
 /// For example, `traverse_ref_with_special_handling_of_binders` cannot be made using only
 /// `traverse_ref`, because `traverse_ref` takes a `FnMut` so we would need to pass multiple
@@ -9,7 +9,7 @@ use std::iter::FromIterator;
 /// preventing exactly this ! So we have to be more clever. The visitor pattern allows us to have
 /// only one mutable thing the whole time: the visitor itself. The visitor can then carry around
 /// multiple closures or just one, and Rust is ok with either. See for example TraverseRefVisitor.
-pub trait ExprFVisitor<'a, SE1, SE2, E1, E2>: Sized {
+pub trait ExprKindVisitor<'a, SE1, SE2, E1, E2>: Sized {
     type Error;
 
     fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error>;
@@ -25,14 +25,14 @@ pub trait ExprFVisitor<'a, SE1, SE2, E1, E2>: Sized {
 
     fn visit(
         self,
-        input: &'a ExprF<SE1, E1>,
-    ) -> Result<ExprF<SE2, E2>, Self::Error> {
+        input: &'a ExprKind<SE1, E1>,
+    ) -> Result<ExprKind<SE2, E2>, Self::Error> {
         visit_ref(self, input)
     }
 }
 
-/// Like `ExprFVisitor`, but by mutable reference
-pub trait ExprFMutVisitor<'a, SE, E>: Sized {
+/// Like `ExprKindVisitor`, but by mutable reference
+pub trait ExprKindMutVisitor<'a, SE, E>: Sized {
     type Error;
 
     fn visit_subexpr(&mut self, subexpr: &'a mut SE)
@@ -49,17 +49,17 @@ pub trait ExprFMutVisitor<'a, SE, E>: Sized {
         self.visit_subexpr(subexpr)
     }
 
-    fn visit(self, input: &'a mut ExprF<SE, E>) -> Result<(), Self::Error> {
+    fn visit(self, input: &'a mut ExprKind<SE, E>) -> Result<(), Self::Error> {
         visit_mut(self, input)
     }
 }
 
 fn visit_ref<'a, V, SE1, SE2, E1, E2>(
     mut v: V,
-    input: &'a ExprF<SE1, E1>,
-) -> Result<ExprF<SE2, E2>, V::Error>
+    input: &'a ExprKind<SE1, E1>,
+) -> Result<ExprKind<SE2, E2>, V::Error>
 where
-    V: ExprFVisitor<'a, SE1, SE2, E1, E2>,
+    V: ExprKindVisitor<'a, SE1, SE2, E1, E2>,
 {
     fn vec<'a, T, U, Err, F: FnMut(&'a T) -> Result<U, Err>>(
         x: &'a [T],
@@ -83,7 +83,7 @@ where
     where
         SE1: 'a,
         T: FromIterator<(Label, SE2)>,
-        V: ExprFVisitor<'a, SE1, SE2, E1, E2>,
+        V: ExprKindVisitor<'a, SE1, SE2, E1, E2>,
     {
         x.into_iter()
             .map(|(k, x)| Ok((k.clone(), v.visit_subexpr(x)?)))
@@ -96,7 +96,7 @@ where
     where
         SE1: 'a,
         T: FromIterator<(Label, Option<SE2>)>,
-        V: ExprFVisitor<'a, SE1, SE2, E1, E2>,
+        V: ExprKindVisitor<'a, SE1, SE2, E1, E2>,
     {
         x.into_iter()
             .map(|(k, x)| {
@@ -111,7 +111,7 @@ where
             .collect()
     }
 
-    use crate::syntax::ExprF::*;
+    use crate::syntax::ExprKind::*;
     Ok(match input {
         Var(v) => Var(v.clone()),
         Lam(l, t, e) => {
@@ -172,14 +172,14 @@ where
 
 fn visit_mut<'a, V, SE, E>(
     mut v: V,
-    input: &'a mut ExprF<SE, E>,
+    input: &'a mut ExprKind<SE, E>,
 ) -> Result<(), V::Error>
 where
-    V: ExprFMutVisitor<'a, SE, E>,
+    V: ExprKindMutVisitor<'a, SE, E>,
 {
     fn vec<'a, V, SE, E>(v: &mut V, x: &'a mut Vec<SE>) -> Result<(), V::Error>
     where
-        V: ExprFMutVisitor<'a, SE, E>,
+        V: ExprKindMutVisitor<'a, SE, E>,
     {
         for x in x {
             v.visit_subexpr(x)?;
@@ -191,7 +191,7 @@ where
         x: &'a mut Option<SE>,
     ) -> Result<(), V::Error>
     where
-        V: ExprFMutVisitor<'a, SE, E>,
+        V: ExprKindMutVisitor<'a, SE, E>,
     {
         if let Some(x) = x {
             v.visit_subexpr(x)?;
@@ -204,7 +204,7 @@ where
     ) -> Result<(), V::Error>
     where
         SE: 'a,
-        V: ExprFMutVisitor<'a, SE, E>,
+        V: ExprKindMutVisitor<'a, SE, E>,
     {
         for (_, x) in x {
             v.visit_subexpr(x)?;
@@ -217,7 +217,7 @@ where
     ) -> Result<(), V::Error>
     where
         SE: 'a,
-        V: ExprFMutVisitor<'a, SE, E>,
+        V: ExprKindMutVisitor<'a, SE, E>,
     {
         for (_, x) in x {
             opt(&mut v, x)?;
@@ -225,7 +225,7 @@ where
         Ok(())
     }
 
-    use crate::syntax::ExprF::*;
+    use crate::syntax::ExprKind::*;
     match input {
         Var(_) | Const(_) | Builtin(_) | BoolLit(_) | NaturalLit(_)
         | IntegerLit(_) | DoubleLit(_) => {}
@@ -293,7 +293,7 @@ pub struct TraverseRefWithBindersVisitor<F1, F2> {
     pub visit_under_binder: F2,
 }
 
-impl<'a, SE, E, SE2, Err, F1, F2> ExprFVisitor<'a, SE, SE2, E, E>
+impl<'a, SE, E, SE2, Err, F1, F2> ExprKindVisitor<'a, SE, SE2, E, E>
     for TraverseRefWithBindersVisitor<F1, F2>
 where
     SE: 'a,
@@ -322,7 +322,7 @@ pub struct TraverseRefVisitor<F1> {
     pub visit_subexpr: F1,
 }
 
-impl<'a, SE, E, SE2, Err, F1> ExprFVisitor<'a, SE, SE2, E, E>
+impl<'a, SE, E, SE2, Err, F1> ExprKindVisitor<'a, SE, SE2, E, E>
     for TraverseRefVisitor<F1>
 where
     SE: 'a,
@@ -343,7 +343,8 @@ pub struct TraverseMutVisitor<F1> {
     pub visit_subexpr: F1,
 }
 
-impl<'a, SE, E, Err, F1> ExprFMutVisitor<'a, SE, E> for TraverseMutVisitor<F1>
+impl<'a, SE, E, Err, F1> ExprKindMutVisitor<'a, SE, E>
+    for TraverseMutVisitor<F1>
 where
     SE: 'a,
     E: 'a,
diff --git a/dhall/src/syntax/binary/decode.rs b/dhall/src/syntax/binary/decode.rs
index f452666..8b73e46 100644
--- a/dhall/src/syntax/binary/decode.rs
+++ b/dhall/src/syntax/binary/decode.rs
@@ -6,7 +6,7 @@ use crate::error::DecodeError;
 use crate::semantics::phase::DecodedExpr;
 use crate::syntax;
 use crate::syntax::{
-    Expr, ExprF, FilePath, FilePrefix, Hash, ImportLocation, ImportMode,
+    Expr, ExprKind, FilePath, FilePrefix, Hash, ImportLocation, ImportMode,
     Integer, InterpolatedText, Label, Natural, RawExpr, Scheme, Span, URL, V,
 };
 
@@ -25,10 +25,10 @@ fn rc<E>(x: RawExpr<E>) -> Expr<E> {
 fn cbor_value_to_dhall(data: &cbor::Value) -> Result<DecodedExpr, DecodeError> {
     use cbor::Value::*;
     use syntax::{BinOp, Builtin, Const};
-    use ExprF::*;
+    use ExprKind::*;
     Ok(rc(match data {
         String(s) => match Builtin::parse(s) {
-            Some(b) => ExprF::Builtin(b),
+            Some(b) => ExprKind::Builtin(b),
             None => match s.as_str() {
                 "True" => BoolLit(true),
                 "False" => BoolLit(false),
@@ -123,7 +123,7 @@ fn cbor_value_to_dhall(data: &cbor::Value) -> Result<DecodedExpr, DecodeError> {
             }
             [U64(4), t] => {
                 let t = cbor_value_to_dhall(&t)?;
-                EmptyListLit(rc(App(rc(ExprF::Builtin(Builtin::List)), t)))
+                EmptyListLit(rc(App(rc(ExprKind::Builtin(Builtin::List)), t)))
             }
             [U64(4), Null, rest @ ..] => {
                 let rest = rest
@@ -139,14 +139,14 @@ fn cbor_value_to_dhall(data: &cbor::Value) -> Result<DecodedExpr, DecodeError> {
             // Old-style optional literals
             [U64(5), t] => {
                 let t = cbor_value_to_dhall(&t)?;
-                App(rc(ExprF::Builtin(Builtin::OptionalNone)), t)
+                App(rc(ExprKind::Builtin(Builtin::OptionalNone)), t)
             }
             [U64(5), t, x] => {
                 let x = cbor_value_to_dhall(&x)?;
                 let t = cbor_value_to_dhall(&t)?;
                 Annot(
                     rc(SomeLit(x)),
-                    rc(App(rc(ExprF::Builtin(Builtin::Optional)), t)),
+                    rc(App(rc(ExprKind::Builtin(Builtin::Optional)), t)),
                 )
             }
             [U64(6), x, y] => {
diff --git a/dhall/src/syntax/binary/encode.rs b/dhall/src/syntax/binary/encode.rs
index c1e7c4c..25a545c 100644
--- a/dhall/src/syntax/binary/encode.rs
+++ b/dhall/src/syntax/binary/encode.rs
@@ -5,8 +5,8 @@ use crate::error::EncodeError;
 use crate::syntax;
 use crate::syntax::map::DupTreeMap;
 use crate::syntax::{
-    Expr, ExprF, FilePrefix, Hash, Import, ImportLocation, ImportMode, Label,
-    Scheme, V,
+    Expr, ExprKind, FilePrefix, Hash, Import, ImportLocation, ImportMode,
+    Label, Scheme, V,
 };
 
 /// Warning: will fail if `expr` contains an `Embed` node.
@@ -46,7 +46,7 @@ where
     use cbor::Value::{String, I64, U64};
     use std::iter::once;
     use syntax::Builtin;
-    use syntax::ExprF::*;
+    use syntax::ExprKind::*;
 
     use self::Serialize::{RecordMap, UnionMap};
     fn expr<E>(x: &Expr<E>) -> self::Serialize<'_, E> {
@@ -110,7 +110,9 @@ where
         SomeLit(x) => ser_seq!(ser; tag(5), null(), expr(x)),
         EmptyListLit(x) => match x.as_ref() {
             App(f, a) => match f.as_ref() {
-                ExprF::Builtin(Builtin::List) => ser_seq!(ser; tag(4), expr(a)),
+                ExprKind::Builtin(Builtin::List) => {
+                    ser_seq!(ser; tag(4), expr(a))
+                }
                 _ => ser_seq!(ser; tag(28), expr(x)),
             },
             _ => ser_seq!(ser; tag(28), expr(x)),
@@ -284,7 +286,7 @@ fn collect_nested_applications<'a, 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) => {
+            ExprKind::App(f, a) => {
                 vec.push(a);
                 go(f, vec)
             }
@@ -306,7 +308,7 @@ fn collect_nested_lets<'a, E>(
         vec: &mut Vec<LetBinding<'a, E>>,
     ) -> &'a Expr<E> {
         match e.as_ref() {
-            ExprF::Let(l, t, v, e) => {
+            ExprKind::Let(l, t, v, e) => {
                 vec.push((l, t, v));
                 go(e, vec)
             }
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index 617348b..e1bb469 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -8,7 +8,7 @@ use pest_consume::{match_nodes, Parser};
 use crate::semantics::phase::Normalized;
 use crate::syntax;
 use crate::syntax::map::{DupTreeMap, DupTreeSet};
-use crate::syntax::ExprF::*;
+use crate::syntax::ExprKind::*;
 use crate::syntax::{
     Double, FilePath, FilePrefix, Hash, ImportLocation, ImportMode, Integer,
     InterpolatedText, InterpolatedTextContents, Label, NaiveDouble, Natural,
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index 7ccc708..75703d2 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -3,9 +3,9 @@ use itertools::Itertools;
 use std::fmt::{self, Display};
 
 /// Generic instance that delegates to subexpressions
-impl<SE: Display + Clone, E: Display> Display for ExprF<SE, E> {
+impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        use crate::syntax::ExprF::*;
+        use crate::syntax::ExprKind::*;
         match self {
             Lam(a, b, c) => {
                 write!(f, "λ({} : {}) → {}", a, b, c)?;
@@ -53,10 +53,10 @@ impl<SE: Display + Clone, E: Display> Display for ExprF<SE, E> {
             Assert(a) => {
                 write!(f, "assert : {}", a)?;
             }
-            ExprF::BinOp(op, a, b) => {
+            ExprKind::BinOp(op, a, b) => {
                 write!(f, "{} {} {}", a, op, b)?;
             }
-            ExprF::App(a, b) => {
+            ExprKind::App(a, b) => {
                 write!(f, "{} {}", a, b)?;
             }
             Field(a, b) => {
@@ -141,7 +141,7 @@ impl<A: Display + Clone> RawExpr<A> {
         f: &mut fmt::Formatter,
         phase: PrintPhase,
     ) -> Result<(), fmt::Error> {
-        use crate::syntax::ExprF::*;
+        use crate::syntax::ExprKind::*;
         use PrintPhase::*;
 
         let needs_paren = match self {
@@ -160,8 +160,8 @@ impl<A: Display + Clone> RawExpr<A> {
                 true
             }
             // Precedence is magically handled by the ordering of BinOps.
-            ExprF::BinOp(op, _, _) if phase > PrintPhase::BinOp(*op) => true,
-            ExprF::App(_, _) if phase > PrintPhase::App => true,
+            ExprKind::BinOp(op, _, _) if phase > PrintPhase::BinOp(*op) => true,
+            ExprKind::App(_, _) if phase > PrintPhase::App => true,
             Field(_, _) | Projection(_, _) | ProjectionByExpr(_, _)
                 if phase > PrintPhase::Import =>
             {
@@ -189,13 +189,13 @@ impl<A: Display + Clone> RawExpr<A> {
                 b.map(|x| x.phase(PrintPhase::App)),
             ),
             Annot(a, b) => Annot(a.phase(Operator), b),
-            ExprF::BinOp(op, a, b) => ExprF::BinOp(
+            ExprKind::BinOp(op, a, b) => ExprKind::BinOp(
                 op,
                 a.phase(PrintPhase::BinOp(op)),
                 b.phase(PrintPhase::BinOp(op)),
             ),
             SomeLit(e) => SomeLit(e.phase(PrintPhase::Import)),
-            ExprF::App(f, a) => ExprF::App(
+            ExprKind::App(f, a) => ExprKind::App(
                 f.phase(PrintPhase::Import),
                 a.phase(PrintPhase::Import),
             ),
@@ -209,7 +209,7 @@ impl<A: Display + Clone> RawExpr<A> {
             f.write_str("(")?;
         }
 
-        // Uses the ExprF<PhasedExpr<_>, _> instance
+        // Uses the ExprKind<PhasedExpr<_>, _> instance
         phased_self.fmt(f)?;
 
         if needs_paren {
diff --git a/serde_dhall/src/serde.rs b/serde_dhall/src/serde.rs
index 9006a08..cf5efc4 100644
--- a/serde_dhall/src/serde.rs
+++ b/serde_dhall/src/serde.rs
@@ -1,7 +1,7 @@
 use std::borrow::Cow;
 
 use dhall::semantics::phase::NormalizedExpr;
-use dhall::syntax::ExprF;
+use dhall::syntax::ExprKind;
 
 use crate::de::{Deserialize, Error, Result};
 use crate::Value;
@@ -31,7 +31,7 @@ impl<'de: 'a, 'a> serde::Deserializer<'de> for Deserializer<'a> {
         V: serde::de::Visitor<'de>,
     {
         use std::convert::TryInto;
-        use ExprF::*;
+        use ExprKind::*;
         match self.0.as_ref().as_ref() {
             NaturalLit(n) => {
                 if let Ok(n64) = (*n).try_into() {