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array-elem-trlg-iter-elision-iter-nrml-close-null.js (2489B)

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