| // Copyright 2018 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Flags: --allow-natives-syntax |
| |
| class Foo extends Promise {}; |
| |
| function f() { |
| return new Promise(r => 88).then(x => 88); |
| } |
| |
| %PrepareFunctionForOptimization(f); |
| |
| let y; |
| |
| y = f(); |
| assertFalse(y instanceof Foo); |
| |
| y = f(); |
| assertFalse(y instanceof Foo); |
| |
| %OptimizeFunctionOnNextCall(f); |
| |
| y = f(); |
| assertFalse(y instanceof Foo); |
| |
| assertTrue(Reflect.defineProperty(Promise, Symbol.species, {value: Foo})); |
| |
| y = f(); |
| assertInstanceof(y, Foo); |
