raise an error instead of a warning on malformed types definitions

typing/typer.ml

@@ -464,9 +464,10 @@ module IType = struct
          warning loc
            ("This definition yields an empty type for " ^ (U.to_string v));
         if (List.length vars) <> (List.length pl) then
-          warning loc
-            ("Definition of type" ^ (U.to_string v) ^ 
-            " contains unused/undeclared type variables");
+          error loc
+            (Printf.sprintf "Definition of type %s contains unused/undeclared type variables" 
+             (U.to_string v)
+            );
         let al =
           let a = Array.make (List.length pl) (Var.mk "dummy")in
           (* XXX here I use pervasive.compare instead of string compare *)
@@ -474,7 +475,7 @@ module IType = struct
           a
         in 
         (v',t,al)
-      ) b b' 
+      ) (List.rev b) (List.rev b') 
     in
     List.iter (fun (v,t,al) ->
       Types.Print.register_global ("",v,Array.map Types.var al) t