// 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: Super need to be called to initialize internals
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.
---*/

class WS1 extends WeakSet {
  constructor() {}
}

assert.throws(ReferenceError, function() {
  new WS1();
});

class WS2 extends WeakSet {
  constructor() {
    super();
  }
}

new WS2();
