RESOLVED WONTFIX247493
Order between initializing x and this.x in strict mode 
https://bugs.webkit.org/show_bug.cgi?id=247493
Summary Order between initializing x and this.x in strict mode
Kanguk Lee
Reported 2022-11-04 09:59:29 PDT
Created attachment 463411 [details] I captured ECMAScript 2022 section 13.15.2. // input.js "use strict"; x = this.x = 0; ________________________________ Hello, Executing the input.js using JSC terminates normally, but it is expected to throw ReferenceError. According to ECMAScript 2022 section 13.15.2: Evaluation of `*AssignmentExpression* : *LeftHandSideExpression* = *AssignmentExpression*`, (link: https://tc39.es/ecma262/2022/multipage/ecmascript-language-expressions.html#sec-assignment-operators-runtime-semantics-evaluation) in line 1-a, *LeftHandSideExpression*, i.e. `x` should be evaluated first and the evaluation result is an unresolvable reference. Therefore PutValue() in line 1-e throws ReferenceError because strict mode is turned on. WebKit version: 615.1.10
Attachments
I captured ECMAScript 2022 section 13.15.2. (1.28 MB, image/png)
2022-11-04 09:59 PDT, Kanguk Lee 		no flags
Details
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Radar WebKit Bug Importer
Comment 1 2022-11-07 16:24:45 PST
<rdar://problem/102064848>
Yijia Huang
Comment 2 2022-11-13 00:15:36 PST
Pull request: https://github.com/WebKit/WebKit/pull/6438
Yusuke Suzuki
Comment 3 2022-11-14 11:03:47 PST
Ross pointed out that this is spec issue actually. https://github.com/WebKit/WebKit/pull/6438#issuecomment-1312694884 https://github.com/WebKit/WebKit/pull/6438#issuecomment-1312922522 We close this since the spec will be upgraded.
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