// Copyright (C) 2016 the V8 project authors. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- esid: sec-generator-function-definitions-runtime-semantics-evaluation es6id: 14.4.14 description: > Abrupt completion returned after protocol violation (and a `return` method is not defined) info: | YieldExpression : yield * AssignmentExpression 1. Let exprRef be the result of evaluating AssignmentExpression. 2. Let value be ? GetValue(exprRef). 3. Let iterator be ? GetIterator(value). 4. Let received be NormalCompletion(undefined). 5. Repeat a. If received.[[Type]] is normal, then [...] b. Else if received.[[Type]] is throw, then i. Let throw be ? GetMethod(iterator, "throw"). ii. If throw is not undefined, then [...] iii. Else, 1. NOTE: If iterator does not have a throw method, this throw is going to terminate the yield* loop. But first we need to give iterator a chance to clean up. 2. Perform ? IteratorClose(iterator, Completion{[[Type]]: normal, [[Value]]: empty, [[Target]]: empty}). 3. NOTE: The next step throws a TypeError to indicate that there was a yield* protocol violation: iterator does not have a throw method. 4. Throw a TypeError exception. 7.4.6 IteratorClose 1. Assert: Type(iterator) is Object. 2. Assert: completion is a Completion Record. 3. Let return be ? GetMethod(iterator, "return"). 4. If return is undefined, return Completion(completion). features: [generators, Symbol.iterator] ---*/ var badIter = {}; var throwCount = 0; var returnCount = 0; var spyResult = { next: function() { return { done: false }; } }; Object.defineProperty(spyResult, 'throw', { get: function() { throwCount += 1; } }); Object.defineProperty(spyResult, 'return', { get: function() { returnCount += 1; } }); badIter[Symbol.iterator] = function() { return spyResult; }; function* g() { try { yield * badIter; } catch (err) { caught = err; } } var iter = g(); var caught; iter.next(); iter.throw(); assert.sameValue(throwCount, 1, '`throw` property access'); assert.sameValue(returnCount, 1, '`return` property access'); assert.sameValue(typeof caught, 'object'); assert.sameValue(caught.constructor, TypeError); reportCompare(0, 0);