2 files changed, 14 insertions, 16 deletions

diff --git a/dhall/src/semantics/tck/tyexpr.rs b/dhall/src/semantics/tck/tyexpr.rs
index ac15ac5..c7b8009 100644
--- a/dhall/src/semantics/tck/tyexpr.rs
+++ b/dhall/src/semantics/tck/tyexpr.rs
@@ -1,3 +1,4 @@
+use crate::error::TypeError;
 use crate::semantics::{Hir, HirKind, NzEnv, TyEnv, Value};
 use crate::syntax::{Const, Span};
 use crate::{NormalizedExpr, ToExprOptions};
@@ -25,16 +26,13 @@ impl TyExpr {
     pub fn ty(&self) -> &Type {
         &self.ty
     }
-    pub fn get_type_tyexpr(&self, env: &TyEnv) -> TyExpr {
-        self.ty()
-            .to_hir(env.as_varenv())
-            .typecheck(env)
-            .expect("Internal type error")
+    pub fn get_type_tyexpr(&self, env: &TyEnv) -> Result<TyExpr, TypeError> {
+        Ok(self.ty().to_hir(env.as_varenv()).typecheck(env)?)
     }
     /// Get the kind (the type of the type) of this value
     // TODO: avoid recomputing so much
-    pub fn get_kind(&self, env: &TyEnv) -> Option<Const> {
-        self.get_type_tyexpr(env).ty().as_const()
+    pub fn get_kind(&self, env: &TyEnv) -> Result<Option<Const>, TypeError> {
+        Ok(self.get_type_tyexpr(env)?.ty().as_const())
     }
 
     pub fn to_hir(&self) -> Hir {
diff --git a/dhall/src/semantics/tck/typecheck.rs b/dhall/src/semantics/tck/typecheck.rs
index b3c9353..377b97e 100644
--- a/dhall/src/semantics/tck/typecheck.rs
+++ b/dhall/src/semantics/tck/typecheck.rs
@@ -53,7 +53,7 @@ fn type_one_layer(
         ExprKind::Lam(binder, annot, body) => {
             let body_ty = body.get_type_tyexpr(
                 &env.insert_type(&binder.clone(), annot.eval(env)),
-            );
+            )?;
             let pi_ekind = ExprKind::Pi(binder.clone(), annot.clone(), body_ty);
             type_one_layer(env, pi_ekind, None, Span::Artificial)?.eval(env)
         }
@@ -139,7 +139,7 @@ fn type_one_layer(
                     return span_err("InvalidListElement");
                 }
             }
-            if x.get_kind(env) != Some(Const::Type) {
+            if x.get_kind(env)? != Some(Const::Type) {
                 return span_err("InvalidListType");
             }
 
@@ -147,7 +147,7 @@ fn type_one_layer(
             Value::from_builtin(Builtin::List).app(t)
         }
         ExprKind::SomeLit(x) => {
-            if x.get_kind(env) != Some(Const::Type) {
+            if x.get_kind(env)? != Some(Const::Type) {
                 return span_err("InvalidOptionalType");
             }
 
@@ -167,7 +167,7 @@ fn type_one_layer(
                 };
 
                 // Check that the fields have a valid kind
-                match v.get_kind(env) {
+                match v.get_kind(env)? {
                     Some(_) => {}
                     None => return span_err("InvalidFieldType"),
                 }
@@ -315,7 +315,7 @@ fn type_one_layer(
             if *x.ty().kind() != ValueKind::from_builtin(Builtin::Bool) {
                 return span_err("InvalidPredicate");
             }
-            if y.get_kind(env) != Some(Const::Type) {
+            if y.get_kind(env)? != Some(Const::Type) {
                 return span_err("IfBranchMustBeTerm");
             }
             if y.ty() != z.ty() {
@@ -350,8 +350,8 @@ fn type_one_layer(
         ExprKind::BinOp(BinOp::RecursiveRecordMerge, x, y) => {
             let ekind = ExprKind::BinOp(
                 BinOp::RecursiveRecordTypeMerge,
-                x.get_type_tyexpr(env),
-                y.get_type_tyexpr(env),
+                x.get_type_tyexpr(env)?,
+                y.get_type_tyexpr(env)?,
             );
             type_one_layer(env, ekind, None, span.clone())?.eval(env)
         }
@@ -413,7 +413,7 @@ fn type_one_layer(
             if l.ty() != r.ty() {
                 return span_err("EquivalenceTypeMismatch");
             }
-            if l.get_kind(env) != Some(Const::Type) {
+            if l.get_kind(env)? != Some(Const::Type) {
                 return span_err("EquivalenceArgumentsMustBeTerms");
             }
 
@@ -582,7 +582,7 @@ fn type_one_layer(
             }
         }
         ExprKind::ToMap(record, annot) => {
-            if record.get_kind(env) != Some(Const::Type) {
+            if record.get_kind(env)? != Some(Const::Type) {
                 return span_err("`toMap` only accepts records of type `Type`");
             }
             let record_t = record.ty();