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// |reftest| async
// This file was procedurally generated from the following sources:
// - src/dstr-binding-for-await/ary-ptrn-elem-id-init-skipped.case
// - src/dstr-binding-for-await/default/for-await-of-async-func-const-async.template
/*---
description: Destructuring initializer is not evaluated when value is not `undefined` (for-await-of statement)
esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
features: [destructuring-binding, async-iteration]
flags: [generated, async]
info: |
IterationStatement :
for await ( ForDeclaration of AssignmentExpression ) Statement
[...]
2. Return ? ForIn/OfBodyEvaluation(ForDeclaration, Statement, keyResult,
lexicalBinding, labelSet, async).
13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation
[...]
4. Let destructuring be IsDestructuring of lhs.
[...]
6. Repeat
[...]
j. If destructuring is false, then
[...]
k. Else
i. If lhsKind is assignment, then
[...]
ii. Else if lhsKind is varBinding, then
[...]
iii. Else,
1. Assert: lhsKind is lexicalBinding.
2. Assert: lhs is a ForDeclaration.
3. Let status be the result of performing BindingInitialization
for lhs passing nextValue and iterationEnv as arguments.
[...]
13.3.3.6 Runtime Semantics: IteratorBindingInitialization
SingleNameBinding : BindingIdentifier Initializer_opt
[...]
6. If Initializer is present and v is undefined, then
[...]
7. If environment is undefined, return PutValue(lhs, v).
7. Return InitializeReferencedBinding(lhs, v).
---*/
var initCount = 0;
function counter() {
initCount += 1;
}
var iterCount = 0;
var asyncIter = (async function*() {
yield* [[null, 0, false, '']];
})();
async function fn() {
for await (const [w = counter(), x = counter(), y = counter(), z = counter()] of asyncIter) {
assert.sameValue(w, null);
assert.sameValue(x, 0);
assert.sameValue(y, false);
assert.sameValue(z, '');
assert.sameValue(initCount, 0);
iterCount += 1;
}
}
fn()
.then(() => assert.sameValue(iterCount, 1, 'iteration occurred as expected'), $DONE)
.then($DONE, $DONE);
|
