| // 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 'package:expect/expect.dart'; |
| |
| // Tests to ensure that narrowing type information does not discard late |
| // sentinel values unintentionally. |
| |
| class Foo<T> { |
| // Since `List<T>` contains a free type variable, any access of [x] will be |
| // immediately followed by a narrowing to the appropriate instantiation of |
| // `List<T>`. This narrowing should not exclude the late sentinel value from |
| // the abstract value. |
| late final List<T> x; |
| } |
| |
| void main() { |
| Foo<int> foo = Foo(); |
| Expect.throws(() => foo.x); |
| foo.x = const []; |
| Expect.isTrue(foo.x.isEmpty); |
| } |