4 files changed, 50 insertions, 40 deletions

diff --git a/dhall/src/lib.rs b/dhall/src/lib.rs
index a4987c6..c329c66 100644
--- a/dhall/src/lib.rs
+++ b/dhall/src/lib.rs
@@ -22,7 +22,9 @@ use crate::error::{EncodeError, Error, TypeError};
 use crate::semantics::parse;
 use crate::semantics::resolve;
 use crate::semantics::resolve::ImportRoot;
-use crate::semantics::{typecheck, typecheck_with, Hir, Nir, NirKind, Tir};
+use crate::semantics::{
+    typecheck, typecheck_with, Hir, Nir, NirKind, Tir, Type,
+};
 use crate::syntax::binary;
 use crate::syntax::{Builtin, Expr};
 
@@ -42,7 +44,10 @@ pub struct Resolved(Hir);
 
 /// A typed expression
 #[derive(Debug, Clone)]
-pub struct Typed(Tir);
+pub struct Typed {
+    hir: Hir,
+    ty: Type,
+}
 
 /// A normalized expression.
 ///
@@ -92,10 +97,10 @@ impl Parsed {
 
 impl Resolved {
     pub fn typecheck(&self) -> Result<Typed, TypeError> {
-        Ok(Typed(typecheck(&self.0)?))
+        Ok(Typed::from_tir(typecheck(&self.0)?))
     }
     pub fn typecheck_with(self, ty: &Normalized) -> Result<Typed, TypeError> {
-        Ok(Typed(typecheck_with(&self.0, ty.to_hir())?))
+        Ok(Typed::from_tir(typecheck_with(&self.0, ty.to_hir())?))
     }
     /// Converts a value back to the corresponding AST expression.
     pub fn to_expr(&self) -> ResolvedExpr {
@@ -104,21 +109,27 @@ impl Resolved {
 }
 
 impl Typed {
+    fn from_tir(tir: Tir<'_>) -> Self {
+        Typed {
+            hir: tir.as_hir().clone(),
+            ty: tir.ty().clone(),
+        }
+    }
     /// Reduce an expression to its normal form, performing beta reduction
     pub fn normalize(&self) -> Normalized {
-        Normalized(self.0.rec_eval_closed_expr())
+        Normalized(self.hir.rec_eval_closed_expr())
     }
 
     /// Converts a value back to the corresponding AST expression.
     fn to_expr(&self) -> ResolvedExpr {
-        self.0.to_expr(ToExprOptions {
+        self.hir.to_expr(ToExprOptions {
             alpha: false,
             normalize: false,
         })
     }
 
     pub(crate) fn get_type(&self) -> Result<Normalized, TypeError> {
-        Ok(Normalized(self.0.ty().clone().into_nir()))
+        Ok(Normalized(self.ty.clone().into_nir()))
     }
 }
 
diff --git a/dhall/src/semantics/resolve/hir.rs b/dhall/src/semantics/resolve/hir.rs
index 346abbf..d421718 100644
--- a/dhall/src/semantics/resolve/hir.rs
+++ b/dhall/src/semantics/resolve/hir.rs
@@ -48,11 +48,11 @@ impl Hir {
         self.span.clone()
     }
 
-    /// Converts a HIR expr back to the corresponding AST expression.
+    /// Converts a closed Hir expr back to the corresponding AST expression.
     pub fn to_expr(&self, opts: ToExprOptions) -> NormalizedExpr {
         hir_to_expr(self, opts, &mut NameEnv::new())
     }
-    /// Converts a HIR expr back to the corresponding AST expression.
+    /// Converts a closed Hir expr back to the corresponding AST expression.
     pub fn to_expr_noopts(&self) -> NormalizedExpr {
         let opts = ToExprOptions {
             normalize: false,
@@ -70,7 +70,10 @@ impl Hir {
     }
 
     /// Typecheck the Hir.
-    pub fn typecheck(&self, env: &TyEnv) -> Result<Tir, TypeError> {
+    pub fn typecheck<'hir>(
+        &'hir self,
+        env: &TyEnv,
+    ) -> Result<Tir<'hir>, TypeError> {
         type_with(env, self, None)
     }
 
@@ -78,6 +81,17 @@ impl Hir {
     pub fn eval(&self, env: impl Into<NzEnv>) -> Nir {
         Nir::new_thunk(env.into(), self.clone())
     }
+    /// Eval a closed Hir (i.e. without free variables). It will actually get evaluated only as
+    /// needed on demand.
+    pub fn eval_closed_expr(&self) -> Nir {
+        self.eval(NzEnv::new())
+    }
+    /// Eval a closed Hir fully and recursively;
+    pub fn rec_eval_closed_expr(&self) -> Nir {
+        let val = self.eval_closed_expr();
+        val.normalize();
+        val
+    }
 }
 
 fn hir_to_expr(
diff --git a/dhall/src/semantics/tck/tir.rs b/dhall/src/semantics/tck/tir.rs
index 908bf8f..aeb7bf9 100644
--- a/dhall/src/semantics/tck/tir.rs
+++ b/dhall/src/semantics/tck/tir.rs
@@ -1,7 +1,7 @@
 use crate::error::{ErrorBuilder, TypeError};
 use crate::semantics::{mkerr, Hir, Nir, NirKind, NzEnv, TyEnv, VarEnv};
 use crate::syntax::{Builtin, Const, Span};
-use crate::{NormalizedExpr, ToExprOptions};
+use crate::NormalizedExpr;
 
 /// The type of a type. 0 is `Type`, 1 is `Kind`, etc...
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Default)]
@@ -17,8 +17,8 @@ pub(crate) struct Type {
 /// A hir expression plus its inferred type.
 /// Stands for "Typed intermediate representation"
 #[derive(Debug, Clone)]
-pub(crate) struct Tir {
-    hir: Hir,
+pub(crate) struct Tir<'hir> {
+    hir: &'hir Hir,
     ty: Type,
 }
 
@@ -106,12 +106,9 @@ impl Type {
     }
 }
 
-impl Tir {
-    pub fn from_hir(hir: &Hir, ty: Type) -> Self {
-        Tir {
-            hir: hir.clone(),
-            ty,
-        }
+impl<'hir> Tir<'hir> {
+    pub fn from_hir(hir: &'hir Hir, ty: Type) -> Self {
+        Tir { hir, ty }
     }
 
     pub fn span(&self) -> Span {
@@ -127,10 +124,6 @@ impl Tir {
     pub fn as_hir(&self) -> &Hir {
         &self.hir
     }
-    /// Converts a closed expression back to the corresponding AST expression.
-    pub fn to_expr(&self, opts: ToExprOptions) -> NormalizedExpr {
-        self.as_hir().to_expr(opts)
-    }
     pub fn to_expr_tyenv(&self, env: &TyEnv) -> NormalizedExpr {
         self.as_hir().to_expr_tyenv(env)
     }
@@ -173,17 +166,6 @@ impl Tir {
                 .to_universe(),
         ))
     }
-    /// Eval a closed Tir (i.e. without free variables). It will actually get evaluated only as
-    /// needed on demand.
-    pub fn eval_closed_expr(&self) -> Nir {
-        self.eval(NzEnv::new())
-    }
-    /// Eval a closed Tir fully and recursively;
-    pub fn rec_eval_closed_expr(&self) -> Nir {
-        let val = self.eval_closed_expr();
-        val.normalize();
-        val
-    }
 }
 
 impl From<Const> for Universe {
diff --git a/dhall/src/semantics/tck/typecheck.rs b/dhall/src/semantics/tck/typecheck.rs
index 42a9165..0787b32 100644
--- a/dhall/src/semantics/tck/typecheck.rs
+++ b/dhall/src/semantics/tck/typecheck.rs
@@ -69,7 +69,7 @@ pub fn mk_span_err<T, S: ToString>(span: Span, msg: S) -> Result<T, TypeError> {
 /// layer.
 fn type_one_layer(
     env: &TyEnv,
-    ekind: ExprKind<Tir>,
+    ekind: ExprKind<Tir<'_>>,
     span: Span,
 ) -> Result<Type, TypeError> {
     let span_err = |msg: &str| mk_span_err(span.clone(), msg);
@@ -703,11 +703,11 @@ fn type_one_layer(
 
 /// `type_with` typechecks an expression in the provided environment. Optionally pass an annotation
 /// to compare with.
-pub(crate) fn type_with(
+pub(crate) fn type_with<'hir>(
     env: &TyEnv,
-    hir: &Hir,
+    hir: &'hir Hir,
     annot: Option<Type>,
-) -> Result<Tir, TypeError> {
+) -> Result<Tir<'hir>, TypeError> {
     let tir = match hir.kind() {
         HirKind::Var(var) => Tir::from_hir(hir, env.lookup(var)),
         HirKind::Expr(ExprKind::Var(_)) => {
@@ -799,12 +799,15 @@ pub(crate) fn type_with(
 
 /// Typecheck an expression and return the expression annotated with types if type-checking
 /// succeeded, or an error if type-checking failed.
-pub(crate) fn typecheck(hir: &Hir) -> Result<Tir, TypeError> {
+pub(crate) fn typecheck<'hir>(hir: &'hir Hir) -> Result<Tir<'hir>, TypeError> {
     type_with(&TyEnv::new(), hir, None)
 }
 
 /// Like `typecheck`, but additionally checks that the expression's type matches the provided type.
-pub(crate) fn typecheck_with(hir: &Hir, ty: Hir) -> Result<Tir, TypeError> {
+pub(crate) fn typecheck_with<'hir>(
+    hir: &'hir Hir,
+    ty: Hir,
+) -> Result<Tir<'hir>, TypeError> {
     let ty = typecheck(&ty)?.eval_to_type(&TyEnv::new())?;
     type_with(&TyEnv::new(), hir, Some(ty))
 }