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array-elem-trlg-iter-rest-rtrn-close-null.js (2501B)

      1 // This file was procedurally generated from the following sources:
      2 // - src/dstr-assignment/array-elem-trlg-iter-rest-rtrn-close-null.case
      3 // - src/dstr-assignment/default/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, generators, 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    7. If AssignmentRestElement is present, then
     32       a. Let status be the result of performing
     33          IteratorDestructuringAssignmentEvaluation of AssignmentRestElement
     34          with iteratorRecord as the argument.
     35    8. If iteratorRecord.[[done]] is false, return IteratorClose(iterator,
     36       status).
     37    9. Return Completion(status).
     38 
     39    7.4.6 IteratorClose( iterator, completion )
     40 
     41    [...]
     42    6. Let innerResult be Call(return, iterator, « »).
     43    7. If completion.[[type]] is throw, return Completion(completion).
     44    8. If innerResult.[[type]] is throw, return Completion(innerResult).
     45 
     46 ---*/
     47 var nextCount = 0;
     48 var iterable = {};
     49 var x;
     50 var iterator = {
     51  next: function() {
     52    nextCount += 1;
     53    // Set an upper-bound to limit unnecessary iteration in non-conformant
     54    // implementations
     55    return { done: nextCount > 10 };
     56  },
     57  return: function() {
     58    return null;
     59  }
     60 };
     61 var iter;
     62 iterable[Symbol.iterator] = function() {
     63  return iterator;
     64 };
     65 
     66 function* g() {
     67 
     68 var counter = 0;
     69 
     70 for ([ x , ...{}[yield] ] of [iterable]) {
     71  
     72  counter += 1;
     73 }
     74 
     75 assert.sameValue(counter, 1);
     76 
     77 }
     78 
     79 iter = g();
     80 iter.next();
     81 
     82 assert.throws(TypeError, function() {
     83  iter.return();
     84 });
     85 
     86 assert.sameValue(nextCount, 1);
     87 
     88 reportCompare(0, 0);