rustboot: If the user tries to instantiate a non-parametric type with type parameters, report the location of the error

Author: pcwalton

src/boot/me/resolve.ml

@@ -324,7 +324,11 @@ let rec lookup_type_by_name
                 log cx "args: %s"
                   (Fmt.fmt_to_str Ast.fmt_app_args args);
             end;
-          let ty = rebuild_ty_under_params cx None ty params args true in
+          let ty =
+            rebuild_ty_under_params
+              ~node_id:(id_of_scope (List.hd scopes))
+              cx None ty params args true
+          in
             iflog cx (fun _ -> log cx "--- lookup_type_by_name %a ==> %a"
                         Ast.sprintf_name name
                         Ast.sprintf_ty ty);

src/boot/me/semant.ml

@@ -1043,6 +1043,7 @@ let rec pretty_ty_str (cx:ctxt) (fallback:(Ast.ty -> string)) (ty:Ast.ty) =
 ;;
 
 let rec rebuild_ty_under_params
+    ?node_id:id_opt
     (cx:ctxt)
     (src_tag:Ast.ty_tag option)
     (ty:Ast.ty)
@@ -1052,7 +1053,7 @@ let rec rebuild_ty_under_params
     : Ast.ty =
   if (Array.length params) <> (Array.length args)
   then
-    err None
+    err id_opt
       "mismatched type-params: %s has %d param(s) but %d given"
       (pretty_ty_str cx (Ast.sprintf_ty ()) ty)
       (Array.length params)