| // Copyright (c) 2018, 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 as 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. |
| /// A compile-time constant type means any type that doesn't contain free type |
| /// variables, so the type expression always resolves to the exact same type. |
| /// @description Checks that an expression of the form [e as T] is accepted if |
| /// [e] is potentially constant |
| /// @author iarkh@unipro.ru |
| |
| import "../../Utils/expect.dart"; |
| |
| class A { |
| const A(); |
| } |
| |
| class B extends A { |
| const B(); |
| } |
| |
| class MyClass { |
| final A a; |
| const MyClass(Object o) : a = o as A; |
| } |
| |
| main() { |
| const MyClass c1 = MyClass(A()); |
| Expect.isTrue(c1.a is A); |
| Expect.runtimeIsType<A>(c1.a); |
| |
| const MyClass c2 = MyClass(B()); |
| Expect.isTrue(c2.a is B); |
| Expect.runtimeIsType<B>(c2.a); |
| } |