Bug 247432

Summary: TypeError is expected when reassigning to `const` during destructuring in for statement
Product: WebKit Reporter: Kanguk Lee <p51lee>
Component: JavaScriptCoreAssignee: Yijia Huang <yijia_huang>
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 09:06:03 PDT
// input.js
const x = 0 ; for ( { x } in { x } ) ;
__________________________________________

Hello,

Executing the input.js using JSC, it is terminated normally.
However, it is expected to throw TypeError since there is an assignment to constant variable.

Running the input.js with JSC results in:

---
$ jsc input.js
// no error
---

while other engines behave like:

---
# V8
$ node input.js
input.js:1: TypeError: Assignment to constant variable.
const x = 0 ; for ( { x } in { x } ) ;
                      ^
TypeError: Assignment to constant variable.
    at input.js:1:23

# GraalJS
$ js input.js
TypeError: Assignment to constant "x"
	at <js> :program(input.js:1:22)
---


WebKit version: 615.1.10
Comment 1 Radar WebKit Bug Importer 2022-11-07 16:18:34 PST
<rdar://problem/102064568>
Comment 2 Yijia Huang 2022-11-10 23:54:56 PST
Pull request: https://github.com/WebKit/WebKit/pull/6390
Comment 3 EWS 2022-11-11 11:11:55 PST
Committed 256580@main (c228e7cdd637): <https://commits.webkit.org/256580@main>

Reviewed commits have been landed. Closing PR #6390 and removing active labels.
Comment 4 Yijia Huang 2022-11-14 10:23:08 PST
*** Bug 247786 has been marked as a duplicate of this bug. ***