js/src/tests/test262/language/statements/for-of/dstr/array-rest-nested-obj-undefined-own.js


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// This file was procedurally generated from the following sources:
// - src/dstr-assignment/array-rest-nested-obj-undefined-own.case
// - src/dstr-assignment/default/for-of.template
/*---
description: When DestructuringAssignmentTarget is an array literal and the iterable emits `undefined` as the only value, an array with a single `undefined` element should be used as the value of the nested DestructuringAssignment. (For..of statement)
esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
features: [destructuring-binding]
flags: [generated]
info: |
    IterationStatement :
      for ( LeftHandSideExpression of AssignmentExpression ) Statement

    1. Let keyResult be the result of performing ? ForIn/OfHeadEvaluation(« »,
       AssignmentExpression, iterate).
    2. Return ? ForIn/OfBodyEvaluation(LeftHandSideExpression, Statement,
       keyResult, assignment, labelSet).

    13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation

    [...]
    4. If destructuring is true and if lhsKind is assignment, then
       a. Assert: lhs is a LeftHandSideExpression.
       b. Let assignmentPattern be the parse of the source text corresponding to
          lhs using AssignmentPattern as the goal symbol.
    [...]
---*/
var x = null;
// Use the the top-level lexical scope for 'length' to provide compatibility with browsers
// where length and name are properties of WindowProxy
let length;

var counter = 0;

for ([...{ 0: x, length }] of [[undefined]]) {
  assert.sameValue(x, undefined);
  assert.sameValue(length, 1);
  counter += 1;
}

assert.sameValue(counter, 1);

reportCompare(0, 0);