| // Copyright (c) 2019, 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. |
| |
| /// @assertion An expression of the form [e is T] or [e is! T] is accepted as a |
| /// potentially and compile-time constant expression if [e] is potentially |
| /// constant or compile-time constant, respectively, and [T] is a compile-time |
| /// constant type. |
| /// @description Checks that an expression of the form [e is! T] is accepted if |
| /// [e] is potentially constant |
| /// @author iarkh@unipro.ru |
| |
| // Requirements=nnbd-strong |
| |
| import "../../../Utils/expect.dart"; |
| |
| class MyClass { |
| final String str; |
| const MyClass(Object? o) : str = o is! String ? "undefined" : o; |
| } |
| |
| main() { |
| const MyClass c1 = MyClass("12345"); |
| Expect.equals("12345", c1.str); |
| |
| const MyClass c2 = MyClass(12); |
| Expect.equals("undefined", c2.str); |
| |
| const MyClass c3 = MyClass(null); |
| Expect.equals("undefined", c3.str); |
| } |