Optimization: since an invariant says that the inferred type of a term is

[helm.git] / helm / ocaml / cic_proof_checking / cicTypeChecker.ml

diff --git a/helm/ocaml/cic_proof_checking/cicTypeChecker.ml b/helm/ocaml/cic_proof_checking/cicTypeChecker.ml
index 137f786ab1fc003e7432605ee82116a0e9d6093c..c4d62986e100a84f7800a6cc99beaaf75179ebc8 100644 (file)
--- a/helm/ocaml/cic_proof_checking/cicTypeChecker.ml
+++ b/helm/ocaml/cic_proof_checking/cicTypeChecker.ml
@@ -1370,12 +1370,19 @@ and type_of_aux' metasenv context t =
        and sort2 = type_of_aux ((Some (name,(C.Decl s)))::context) t in
         sort_of_prod context (name,s) (sort1,sort2)
    | C.Lambda (n,s,t) ->
-       let sort1 = type_of_aux context s
-       and type2 = type_of_aux ((Some (n,(C.Decl s)))::context) t in
-        let sort2 = type_of_aux ((Some (n,(C.Decl s)))::context) type2 in
-         (* only to check if the product is well-typed *)
-         let _ = sort_of_prod context (n,s) (sort1,sort2) in
-          C.Prod (n,s,type2)
+       let sort1 = type_of_aux context s in
+       (match R.whd context sort1 with
+           C.Meta _
+         | C.Sort _ -> ()
+         | _ ->
+           raise
+            (TypeCheckerFailure (sprintf
+              "Not well-typed lambda-abstraction: the source %s should be a
+               type; instead it is a term of type %s" (CicPp.ppterm s)
+                (CicPp.ppterm sort1)))
+       ) ;
+       let type2 = type_of_aux ((Some (n,(C.Decl s)))::context) t in
+        C.Prod (n,s,type2)
    | C.LetIn (n,s,t) ->
       (* only to check if s is well-typed *)
       let ty = type_of_aux context s in