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// |reftest| shell-option(--enable-explicit-resource-management) skip-if(!(this.hasOwnProperty('getBuildConfiguration')&&getBuildConfiguration('explicit-resource-management'))||!xulRuntime.shell) async -- explicit-resource-management is not enabled unconditionally, requires shell-options
// Copyright (C) 2023 Ron Buckton. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-let-and-const-declarations-runtime-semantics-evaluation
description: An 'await using' implies an Await occurs if the statement is evaluated, even if all initializers are 'null' or 'undefined'
info: |
RS: Evaluation
AwaitUsingDeclaration : CoverAwaitExpressionAndAwaitUsingDeclarationHead BindingList ;
1. Perform ? BindingEvaluation of BindingList with argument async-dispose.
2. Return empty.
RS: BindingEvaluation
LexicalBinding : BindingIdentifier Initializer
...
5. Return ? InitializeReferencedBinding(lhs, value, hint).
InitializeReferencedBinding ( V, W )
...
4. Return ? base.InitializeBinding(V.[[ReferencedName]], W).
InitializeBinding ( N, V, hint )
...
2. If hint is not normal, perform ? AddDisposableResource(envRec.[[DisposeCapability]], V, hint).
...
AddDisposableResource ( disposeCapability, V, hint [, method ] )
1. If method is not present then,
a. If V is either null or undefined and hint is sync-dispose, then
i. Return unused.
b. Let resource be ? CreateDisposableResource(V, hint).
...
CreateDisposableResource ( V, hint [ , method ] )
1. If method is not present, then
a. If V is either null or undefined, then
i. Set V to undefined.
ii. Set method to undefined.
...
...
3. Return the DisposableResource Record { [[ResourceValue]]: V, [[Hint]]: hint, [[DisposeMethod]]: method }.
DisposeResources ( disposeCapability, completion )
1. For each resource of disposeCapability.[[DisposableResourceStack]], in reverse list order, do
a. Let result be Dispose(resource.[[ResourceValue]], resource.[[Hint]], resource.[[DisposeMethod]]).
b. If result.[[Type]] is throw, then
i. If completion.[[Type]] is throw, then
1. Set result to result.[[Value]].
2. Let suppressed be completion.[[Value]].
3. Let error be a newly created SuppressedError object.
4. Perform ! CreateNonEnumerableDataPropertyOrThrow(error, "error", result).
5. Perform ! CreateNonEnumerableDataPropertyOrThrow(error, "suppressed", suppressed).
6. Set completion to ThrowCompletion(error).
ii. Else,
1. Set completion to result.
2. Return completion.
Dispose ( V, hint, method )
1. If method is undefined, let result be undefined.
2. Else, let result be ? Call(method, V).
3. If hint is async-dispose, then
a. Perform ? Await(result).
4. Return undefined.
flags: [async]
includes: [asyncHelpers.js]
features: [explicit-resource-management]
---*/
asyncTest(async function () {
var isRunningInSameMicrotask = true;
var wasStartedInSameMicrotask = false;
var didEvaluatePrecedingBlockStatementsInSameMicrotask = false;
var didEvaluateFollowingBlockStatementsInSameMicrotask = false;
var wasRunningInSameMicrotask = false;
async function f() {
wasStartedInSameMicrotask = isRunningInSameMicrotask;
{
didEvaluatePrecedingBlockStatementsInSameMicrotask = isRunningInSameMicrotask;
await using _ = null;
didEvaluateFollowingBlockStatementsInSameMicrotask = isRunningInSameMicrotask;
}
wasRunningInSameMicrotask = isRunningInSameMicrotask;
}
var p = f();
isRunningInSameMicrotask = false;
await p;
assert.sameValue(wasStartedInSameMicrotask, true, 'Expected async function containing `await using` to start in the same microtask');
assert.sameValue(didEvaluatePrecedingBlockStatementsInSameMicrotask, true, 'Expected block statements preceding `await using` to be evaluated in the same microtask');
assert.sameValue(didEvaluateFollowingBlockStatementsInSameMicrotask, true, 'Expected block statements following `await using` to be evaluated in the same microtask');
assert.sameValue(wasRunningInSameMicrotask, false, 'Expected statements following the block containing evaluated `await using` to evaluate in a different microtask');
});