No need to track the absence of `Span`s at the type level

4 files changed, 36 insertions, 39 deletions

diff --git a/dhall/src/phase/binary.rs b/dhall/src/phase/binary.rs
index f4a9cc1..3292617 100644
--- a/dhall/src/phase/binary.rs
+++ b/dhall/src/phase/binary.rs
@@ -631,14 +631,12 @@ where
         ImportLocation::Remote(url) => {
             match &url.headers {
                 None => ser_seq.serialize_element(&Null)?,
-                Some(location_hashed) => {
-                    ser_seq.serialize_element(&self::Serialize::Expr(
-                        &SubExpr::from_expr_no_note(ExprF::Embed(Import {
-                            mode: ImportMode::Code,
-                            location_hashed: location_hashed.as_ref().clone(),
-                        })),
-                    ))?
-                }
+                Some(location_hashed) => ser_seq.serialize_element(
+                    &self::Serialize::Expr(&rc(ExprF::Embed(Import {
+                        mode: ImportMode::Code,
+                        location_hashed: location_hashed.as_ref().clone(),
+                    }))),
+                )?,
             };
             ser_seq.serialize_element(&url.authority)?;
             for p in &url.path {
@@ -689,13 +687,13 @@ impl<'a> serde::ser::Serialize for Serialize<'a> {
     }
 }
 
-fn collect_nested_applications<'a, N, E>(
-    e: &'a SubExpr<N, E>,
-) -> (&'a SubExpr<N, E>, Vec<&'a SubExpr<N, E>>) {
-    fn go<'a, N, E>(
-        e: &'a SubExpr<N, E>,
-        vec: &mut Vec<&'a SubExpr<N, E>>,
-    ) -> &'a SubExpr<N, E> {
+fn collect_nested_applications<'a, E>(
+    e: &'a SubExpr<E>,
+) -> (&'a SubExpr<E>, Vec<&'a SubExpr<E>>) {
+    fn go<'a, E>(
+        e: &'a SubExpr<E>,
+        vec: &mut Vec<&'a SubExpr<E>>,
+    ) -> &'a SubExpr<E> {
         match e.as_ref() {
             ExprF::App(f, a) => {
                 vec.push(a);
@@ -709,16 +707,15 @@ fn collect_nested_applications<'a, N, E>(
     (e, vec)
 }
 
-type LetBinding<'a, N, E> =
-    (&'a Label, &'a Option<SubExpr<N, E>>, &'a SubExpr<N, E>);
+type LetBinding<'a, E> = (&'a Label, &'a Option<SubExpr<E>>, &'a SubExpr<E>);
 
-fn collect_nested_lets<'a, N, E>(
-    e: &'a SubExpr<N, E>,
-) -> (&'a SubExpr<N, E>, Vec<LetBinding<'a, N, E>>) {
-    fn go<'a, N, E>(
-        e: &'a SubExpr<N, E>,
-        vec: &mut Vec<LetBinding<'a, N, E>>,
-    ) -> &'a SubExpr<N, E> {
+fn collect_nested_lets<'a, E>(
+    e: &'a SubExpr<E>,
+) -> (&'a SubExpr<E>, Vec<LetBinding<'a, E>>) {
+    fn go<'a, E>(
+        e: &'a SubExpr<E>,
+        vec: &mut Vec<LetBinding<'a, E>>,
+    ) -> &'a SubExpr<E> {
         match e.as_ref() {
             ExprF::Let(l, t, v, e) => {
                 vec.push((l, t, v));
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 27a6901..8c93889 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::fmt::Display;
 use std::path::Path;
 
-use dhall_syntax::{Const, Import, Span, SubExpr, X};
+use dhall_syntax::{Const, Import, SubExpr, X};
 
 use crate::core::thunk::{Thunk, TypedThunk};
 use crate::core::value::Value;
@@ -17,10 +17,10 @@ pub(crate) mod parse;
 pub(crate) mod resolve;
 pub(crate) mod typecheck;
 
-pub type ParsedSubExpr = SubExpr<Span, Import>;
-pub type DecodedSubExpr = SubExpr<X, Import>;
-pub type ResolvedSubExpr = SubExpr<Span, Normalized>;
-pub type NormalizedSubExpr = SubExpr<X, X>;
+pub type ParsedSubExpr = SubExpr<Import>;
+pub type DecodedSubExpr = SubExpr<Import>;
+pub type ResolvedSubExpr = SubExpr<Normalized>;
+pub type NormalizedSubExpr = SubExpr<X>;
 
 #[derive(Debug, Clone)]
 pub struct Parsed(ParsedSubExpr, ImportRoot);
diff --git a/dhall/src/phase/parse.rs b/dhall/src/phase/parse.rs
index 734f6e1..9f3f2f4 100644
--- a/dhall/src/phase/parse.rs
+++ b/dhall/src/phase/parse.rs
@@ -25,7 +25,7 @@ pub fn parse_str(s: &str) -> Result<Parsed, Error> {
 pub fn parse_binary(data: &[u8]) -> Result<Parsed, Error> {
     let expr = crate::phase::binary::decode(data)?;
     let root = ImportRoot::LocalDir(std::env::current_dir()?);
-    Ok(Parsed(expr.note_absurd(), root))
+    Ok(Parsed(expr, root))
 }
 
 pub fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
@@ -33,5 +33,5 @@ pub fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
     File::open(f)?.read_to_end(&mut buffer)?;
     let expr = crate::phase::binary::decode(&buffer)?;
     let root = ImportRoot::LocalDir(f.parent().unwrap().to_owned());
-    Ok(Parsed(expr.note_absurd(), root))
+    Ok(Parsed(expr, root))
 }
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index a19e1ca..ecf9793 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -1,8 +1,8 @@
 use std::collections::HashMap;
 
 use dhall_syntax::{
-    rc, Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label, Span,
-    SubExpr, X,
+    rc, Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label, SubExpr,
+    X,
 };
 
 use crate::core::context::{NormalizationContext, TypecheckContext};
@@ -214,7 +214,7 @@ macro_rules! make_type {
     };
 }
 
-fn type_of_builtin(b: Builtin) -> Expr<X, X> {
+fn type_of_builtin(b: Builtin) -> Expr<X> {
     use dhall_syntax::Builtin::*;
     match b {
         Bool | Natural | Integer | Double | Text => make_type!(Type),
@@ -303,7 +303,7 @@ fn type_of_builtin(b: Builtin) -> Expr<X, X> {
 /// and turn it into a type, typechecking it along the way.
 pub fn mktype(
     ctx: &TypecheckContext,
-    e: SubExpr<Span, Normalized>,
+    e: SubExpr<Normalized>,
 ) -> Result<Type, TypeError> {
     Ok(type_with(ctx, e)?.to_type())
 }
@@ -326,7 +326,7 @@ enum Ret {
 /// normalized as well.
 fn type_with(
     ctx: &TypecheckContext,
-    e: SubExpr<Span, Normalized>,
+    e: SubExpr<Normalized>,
 ) -> Result<Typed, TypeError> {
     use dhall_syntax::ExprF::{Annot, Embed, Lam, Let, Pi, Var};
 
@@ -1002,7 +1002,7 @@ fn type_last_layer(
 /// `typeOf` is the same as `type_with` with an empty context, meaning that the
 /// expression must be closed (i.e. no free variables), otherwise type-checking
 /// will fail.
-fn type_of(e: SubExpr<Span, Normalized>) -> Result<Typed, TypeError> {
+fn type_of(e: SubExpr<Normalized>) -> Result<Typed, TypeError> {
     let ctx = TypecheckContext::new();
     let e = type_with(&ctx, e)?;
     // Ensure `e` has a type (i.e. `e` is not `Sort`)
@@ -1015,8 +1015,8 @@ pub fn typecheck(e: Resolved) -> Result<Typed, TypeError> {
 }
 
 pub fn typecheck_with(e: Resolved, ty: &Type) -> Result<Typed, TypeError> {
-    let expr: SubExpr<_, _> = e.0;
-    let ty: SubExpr<_, _> = ty.to_expr().absurd();
+    let expr: SubExpr<_> = e.0;
+    let ty: SubExpr<_> = ty.to_expr().absurd();
     type_of(expr.rewrap(ExprF::Annot(expr.clone(), ty)))
 }
 pub fn skip_typecheck(e: Resolved) -> Typed {