// Copyright (C) 2016 the V8 project authors. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- es6id: 23.2.1 description: Subclassing the Set object info: | 23.2.1 The Set Constructor ... The Set constructor is designed to be subclassable. It may be used as the value in an extends clause of a class definition. Subclass constructors that intend to inherit the specified Set behaviour must include a super call to the Set constructor to create and initialize the subclass instance with the internal state necessary to support the Set.prototype built-in methods. ---*/ class S extends Set {} var set = new S([{}, {}]); assert.sameValue(set.size, 2); set.add({}); assert.sameValue(set.size, 3); reportCompare(0, 0);