// Copyright (C) 2017 Mozilla Corporation. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-generator-function-definitions-runtime-semantics-evaluation
description: >
If <iterator>.return is an object emulating `undefined` (e.g. `document.all`
in browsers), it shouldn't be treated as if it were actually `undefined` by
the yield* operator.
features: [generators, IsHTMLDDA]
---*/
var IsHTMLDDA = $262.IsHTMLDDA;
var iter = {
[Symbol.iterator]() { return this; },
next() { return {}; },
return: IsHTMLDDA,
};
var outer = (function*() { yield* iter; })();
outer.next();
assert.throws(TypeError, function() {
// `IsHTMLDDA` is called here with `iter` as `this` and `emptyString` as the
// sole argument, and it's specified to return `null` under these conditions.
// As `iter`'s iteration isn't ending because of a throw, the iteration
// protocol will then throw a `TypeError` because `null` isn't an object.
var emptyString = "";
outer.return(emptyString);
});