| // Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| import "dart:async"; |
| |
| T id<T>(T value) => value; |
| |
| main() async { |
| FutureOr<int> x = 1 + id(1); |
| |
| FutureOr<int> y = 1 + id(1) |
| ..checkStaticType<Exactly<int>>(); |
| FutureOr<int> z = 1 + contextType(1) |
| ..checkStaticType<Exactly<int>>(); |
| } |
| |
| extension<T> on T { |
| void checkStaticType<R extends Exactly<T>>() {} |
| } |
| |
| typedef Exactly<T> = T Function(T); |
| T contextType<T>(Object? o) => o as T; |
