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// Copyright (C) 2016 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
es6id: 23.4.1
description: Subclassing the WeakSet object
info: |
23.4.1 The WeakSet Constructor
...
The WeakSet 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 WeakSet behaviour must include a super call to
the WeakSet constructor to create and initialize the subclass instance with
the internal state necessary to support the WeakSet.prototype built-in
methods.
features: [WeakSet]
---*/
class WS extends WeakSet {}
var set = new WS();
var obj = {};
assert.sameValue(set.has(obj), false);
set.add(obj);
assert.sameValue(set.has(obj), true);
reportCompare(0, 0);