don't allow @:using on typedef for now (#8188)

src/typing/typeloadModule.ml

@@ -249,6 +249,7 @@ let module_pass_1 ctx m tdecls loadp =
 		| ETypedef d ->
 			let name = fst d.d_name in
 			if starts_with name '$' then error "Type names starting with a dollar are not allowed" p;
+			if has_meta Meta.Using d.d_meta then error "@:using on typedef is not allowed" p;
 			pt := Some p;
 			let priv = List.mem EPrivate d.d_flags in
 			let path = make_path name priv in