| // Copyright (c) 2011, 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 Let v be a local variable or a formal parameter. An is-expression |
| /// of the form v is T shows that v has type T iff T is more specific than the |
| /// type S of the expression v and both T != dynamic and S != dynamic. |
| /// @description Checks that if T is more specific than S, and neither of them |
| /// is dynamic, then is-expression shows that v has type T. |
| /// @author ilya |
| |
| |
| class C {} |
| class D extends C { f() {} } |
| |
| f(C x) { |
| C y = x; |
| |
| x is D ? x.f() : null; // formal parameter |
| y is D ? y.f() : null; // local variable |
| } |
| |
| main() { |
| f(new D()); |
| } |