star-rhs-iter-rtrn-rtrn-get-err.js (1734B)
1 // Copyright (C) 2016 the V8 project authors. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 /*--- 4 esid: sec-generator-function-definitions-runtime-semantics-evaluation 5 es6id: 14.4.14 6 description: Abrupt completion returned when accessing iterator `return` method 7 info: | 8 YieldExpression : yield * AssignmentExpression 9 10 1. Let exprRef be the result of evaluating AssignmentExpression. 11 2. Let value be ? GetValue(exprRef). 12 3. Let iterator be ? GetIterator(value). 13 4. Let received be NormalCompletion(undefined). 14 5. Repeat 15 a. If received.[[Type]] is normal, then 16 [...] 17 b. Else if received.[[Type]] is throw, then 18 [...] 19 c. Else, 20 i. Assert: received.[[Type]] is return. 21 ii. Let return be ? GetMethod(iterator, "return"). 22 features: [generators, Symbol.iterator] 23 ---*/ 24 25 var thrown = new Test262Error(); 26 var badIter = {}; 27 var callCount = 0; 28 var poisonedReturn = { 29 next: function() { 30 return { done: false }; 31 } 32 }; 33 Object.defineProperty(poisonedReturn, 'throw', { 34 get: function() { 35 callCount += 1; 36 } 37 }); 38 Object.defineProperty(poisonedReturn, 'return', { 39 get: function() { 40 throw thrown; 41 } 42 }); 43 badIter[Symbol.iterator] = function() { 44 return poisonedReturn; 45 }; 46 function* g() { 47 try { 48 yield * badIter; 49 } catch (err) { 50 caught = err; 51 } 52 } 53 var iter = g(); 54 var result, caught; 55 56 iter.next(); 57 58 assert.sameValue(caught, undefined, '`return` property not accessed eagerly'); 59 60 result = iter.return(); 61 62 assert.sameValue(result.value, undefined); 63 assert.sameValue(result.done, true); 64 assert.sameValue(caught, thrown); 65 assert.sameValue(callCount, 0, 'iterator `throw` property is not accessed'); 66 67 reportCompare(0, 0);