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async-gen-decl-dstr-array-elem-trlg-iter-elision-iter-nrml-close-null.js (2751B)

      1 // |reftest| async
      2 // This file was procedurally generated from the following sources:
      3 // - src/dstr-assignment-for-await/array-elem-trlg-iter-elision-iter-nrml-close-null.case
      4 // - src/dstr-assignment-for-await/default/async-gen-decl.template
      5 /*---
      6 description: IteratorClose throws a TypeError when `return` returns a non-Object value (for-await-of statement in an async generator declaration)
      7 esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
      8 features: [Symbol.iterator, destructuring-binding, async-iteration]
      9 flags: [generated, async]
     10 info: |
     11    IterationStatement :
     12      for await ( LeftHandSideExpression of AssignmentExpression ) Statement
     13 
     14    1. Let keyResult be the result of performing ? ForIn/OfHeadEvaluation(« »,
     15       AssignmentExpression, iterate).
     16    2. Return ? ForIn/OfBodyEvaluation(LeftHandSideExpression, Statement,
     17       keyResult, assignment, labelSet).
     18 
     19    13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation
     20 
     21    [...]
     22    5. If destructuring is true and if lhsKind is assignment, then
     23       a. Assert: lhs is a LeftHandSideExpression.
     24       b. Let assignmentPattern be the parse of the source text corresponding to
     25          lhs using AssignmentPattern as the goal symbol.
     26    [...]
     27 
     28    ArrayAssignmentPattern :
     29        [ AssignmentElementList , Elisionopt AssignmentRestElementopt ]
     30 
     31    [...]
     32    6. If Elision is present, then
     33       a. Let status be the result of performing
     34          IteratorDestructuringAssignmentEvaluation of Elision with
     35          iteratorRecord as the argument.
     36       b. If status is an abrupt completion, then
     37          [...]
     38    8. If iteratorRecord.[[done]] is false, return IteratorClose(iterator,
     39       status).
     40 
     41    7.4.6 IteratorClose( iterator, completion )
     42 
     43    [...]
     44    6. Let innerResult be Call(return, iterator, « »).
     45    7. If completion.[[type]] is throw, return Completion(completion).
     46    8. If innerResult.[[type]] is throw, return Completion(innerResult).
     47    9. If Type(innerResult.[[value]]) is not Object, throw a TypeError
     48       exception.
     49 
     50 ---*/
     51 let x;
     52 let nextCount = 0;
     53 let iterator = {
     54  next() {
     55    nextCount += 1;
     56    // Set an upper-bound to limit unnecessary iteration in non-conformant
     57    // implementations
     58    return { done: nextCount > 10 };
     59  },
     60  return() {
     61    return null;
     62  }
     63 };
     64 let iterable = {
     65  [Symbol.iterator]() {
     66    return iterator;
     67  }
     68 };
     69 
     70 
     71 let iterCount = 0;
     72 async function * fn() {
     73  for await ([ x , , ] of [iterable]) {
     74    
     75    iterCount += 1;
     76  }
     77 }
     78 
     79 let promise = fn().next();
     80 
     81 promise.then(() => $DONE('Promise incorrectly fulfilled.'), ({ constructor }) => {
     82  assert.sameValue(iterCount, 0);
     83  assert.sameValue(nextCount, 2);
     84  assert.sameValue(constructor, TypeError);
     85 }).then($DONE, $DONE);