Bug 189799 – [JSC] ForStatement should call CreatePerIterationEnvironment before first iteration

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Dasa Paddock]

Test code:

let callback1;
let callbacks2 = new Array();
let callbacks3 = new Array();

for (
    let i = (callback1 = () => i, 0);
    callbacks2.push(() => i), i < 5;
    callbacks3.push(() => i), i++) {
    // loop body
    i++;
}

console.log(callback1());
console.log(callbacks2[0]());
console.log(callbacks3[0]());

Expected output (works in Chrome and Firefox)

0
1
3

Actual output in Safari TP 65:

1
1
3

Note: I found this test code at: https://github.com/Microsoft/TypeScript/issues/17632

[Radar WebKit Bug Importer]

<rdar://problem/44730906>

[Saam Barati]

Thanks for the report. It looks like Chrome and Firefox are correct w.r.t the spec:
https://tc39.github.io/ecma262/#sec-for-statement-runtime-semantics-labelledevaluation

[Rick Waldron]

Just marking this as "covered" in Test262. https://github.com/tc39/test262/blob/master/test/language/statements/for/scope-body-lex-open.js

[Dasa Paddock]

I'm not sure when this was fixed, but I'm unable to repro in Safari 15.3.

[Dasa Paddock]

Sorry for the noise, this is still broken in Safari 15.3 and Safari TP 139.

[Dasa Paddock]

This is still broken in Safari TP 177.

[Alexey Shvayka]

*** Bug 257677 has been marked as a duplicate of this bug. ***

[Alexey Shvayka]

Pull request: https://github.com/WebKit/WebKit/pull/19403

[EWS]

Committed 269653@main (f32cd0f7cb79): <https://commits.webkit.org/269653@main>

Reviewed commits have been landed. Closing PR #19403 and removing active labels.