| // 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 An if statement of the form if (b) s1 else s2. |
| /// If: |
| /// • b shows that a variable v has type T . |
| /// • v is not potentially mutated in s1 or within a closure. |
| /// • If the variable v is accessed by a closure in s1 then the variable v is |
| /// not potentially mutated anywhere in the scope of v. |
| /// Then the type of v is known to be T in s1. |
| /// @description Checks that if b shows that v has type T, v is not potentially |
| /// mutated in s1 and not captured by any closure then the type of v is known to |
| /// be T in s1, even if v is potentially mutated elsewhere in its scope. |
| /// @author ilya |
| |
| |
| class C {} |
| class D extends C { |
| f() {} |
| } |
| |
| // formal parameter |
| f1(C x) { |
| var y; |
| closure () => y = 1; |
| |
| if (x is D) { |
| closure(); |
| x.f(); |
| } else |
| x = new C(); |
| } |
| |
| // local variable |
| f2(C z) { |
| C x = z; |
| var y; |
| closure () => y = 1; |
| |
| if (x is D) { |
| closure(); |
| x.f(); |
| } else |
| x = new C(); |
| } |
| |
| main() { |
| f1(new D()); |
| f2(new D()); |
| } |