Bug 247435

Summary: Property access of sparse array in LHS throws unexpected `SyntaxError`
Product: WebKit Reporter: Kanguk Lee <p51lee>
Component: JavaScriptCoreAssignee: Yusuke Suzuki <ysuzuki>
Status: RESOLVED FIXED    
Severity: Normal CC: mark.lam, webkit-bug-importer, ysuzuki
Priority: P2 Keywords: InRadar
Version: WebKit Local Build   
Hardware: Unspecified   
OS: Unspecified   

Description Kanguk Lee 2022-11-03 09:16:47 PDT
// input.js
[ + 0 , ] [ 0 ] = 0 ;
// Note: this is fine
// [ 0 , ] [ 0 ] = 0 ;
_____________________

Hello,

Executing the input.js using JSC throws SyntaxError, but it is expected to be terminated normally.

Running the input.js with JSC gives

---
$ jsc input.js
Exception: SyntaxError: Left hand side of operator '=' must be a reference.
at input.js:1
---

while other engines behave like

---
# V8
$ node input.js
// no error

# GraalJS
$ js input.js
// no error
---


WebKit version: 615.1.10
Comment 1 Radar WebKit Bug Importer 2022-11-07 16:41:11 PST
<rdar://problem/102065657>
Comment 2 Yusuke Suzuki 2022-11-07 23:06:54 PST
Pull request: https://github.com/WebKit/WebKit/pull/6241
Comment 3 EWS 2022-11-08 17:48:13 PST
Committed 256471@main (3b17285b1ce6): <https://commits.webkit.org/256471@main>

Reviewed commits have been landed. Closing PR #6241 and removing active labels.