JSTests/test262/test/language/statements/for-await-of/async-gen-decl-dstr-array-elem-trlg-iter-elision-iter-nrml-close-null.js

// This file was procedurally generated from the following sources:
// - src/dstr-assignment-for-await/array-elem-trlg-iter-elision-iter-nrml-close-null.case
// - src/dstr-assignment-for-await/default/async-gen-decl.template
/*---
description: IteratorClose throws a TypeError when `return` returns a non-Object value (for-await-of statement in an async generator declaration)
esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
features: [Symbol.iterator, destructuring-binding, async-iteration]
flags: [generated, async]
info: |
    IterationStatement :
      for await ( 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

    [...]
    5. 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.
    [...]

    ArrayAssignmentPattern :
        [ AssignmentElementList , Elisionopt AssignmentRestElementopt ]

    [...]
    6. If Elision is present, then
       a. Let status be the result of performing
          IteratorDestructuringAssignmentEvaluation of Elision with
          iteratorRecord as the argument.
       b. If status is an abrupt completion, then
          [...]
    8. If iteratorRecord.[[done]] is false, return IteratorClose(iterator,
       status).

    7.4.6 IteratorClose( iterator, completion )

    [...]
    6. Let innerResult be Call(return, iterator, « »).
    7. If completion.[[type]] is throw, return Completion(completion).
    8. If innerResult.[[type]] is throw, return Completion(innerResult).
    9. If Type(innerResult.[[value]]) is not Object, throw a TypeError
       exception.

---*/
let x;
let nextCount = 0;
let iterator = {
  next() {
    nextCount += 1;
    // Set an upper-bound to limit unnecessary iteration in non-conformant
    // implementations
    return { done: nextCount > 10 };
  },
  return() {
    return null;
  }
};
let iterable = {
  [Symbol.iterator]() {
    return iterator;
  }
};


let iterCount = 0;
async function * fn() {
  for await ([ x , , ] of [iterable]) {
    
    iterCount += 1;
  }
}

let promise = fn().next();

promise.then(() => $DONE('Promise incorrectly fulfilled.'), ({ constructor }) => {
  assert.sameValue(iterCount, 0);
  assert.sameValue(nextCount, 2);
  assert.sameValue(constructor, TypeError);
}).then($DONE, $DONE);