diff --git a/typing/mtype.ml b/typing/mtype.ml
index 0b4805c14..417697397 100644
--- a/typing/mtype.ml
+++ b/typing/mtype.ml
@@ -28,6 +28,9 @@ let rec scrape env mty =
       end
   | _ -> mty
 
+let freshen mty =
+  Subst.modtype Subst.identity mty
+
 let rec strengthen env mty p =
   match scrape env mty with
     Tmty_signature sg ->
diff --git a/typing/mtype.mli b/typing/mtype.mli
index ee720be28..abb66b969 100644
--- a/typing/mtype.mli
+++ b/typing/mtype.mli
@@ -20,6 +20,9 @@ val scrape: Env.t -> module_type -> module_type
         (* Expand toplevel module type abbreviations
            till hitting a "hard" module type (signature, functor,
            or abstract module type ident. *)
+val freshen: module_type -> module_type
+        (* Return an alpha-equivalent copy of the given module type
+           where bound identifiers are fresh. *)
 val strengthen: Env.t -> module_type -> Path.t -> module_type
         (* Strengthen abstract type components relative to the
            given path. *)
diff --git a/typing/typemod.ml b/typing/typemod.ml
index 00e87b60e..294f8a005 100644
--- a/typing/typemod.ml
+++ b/typing/typemod.ml
@@ -237,7 +237,7 @@ let rec transl_modtype env smty =
           (fun sg (lid, sdecl) ->
             merge_constraint env smty.pmty_loc sg lid sdecl)
           init_sg constraints in
-      Tmty_signature final_sg
+      Mtype.freshen (Tmty_signature final_sg)
       
 and transl_signature env sg =
   let type_names = ref StringSet.empty