Bug 256245

Summary:	Improve error message for code like "var {a} = undefined;"
Product:	WebKit	Reporter:	Jarred Sumner <jarred>
Component:	JavaScriptCore	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	mark.lam, webkit-bug-importer, ysuzuki
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Jarred Sumner 2023-05-02 22:31:23 PDT

Currently, the following code:

> await Promise.resolve(undefined).then(({default: a}) => a.true())

Produces the following messages:

> TypeError: Right side of assignment cannot be destructured

Instead, something closer to V8's message would be clearer:

> TypeError: Cannot read properties of undefined


It looks like the message is generated here:

https://github.com/WebKit/WebKit/blob/8c684cfbe8afa5cb7eea0e46408cbdd31e920ba1/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp#L5607

It looks like the object can be at least null or undefined when this error is thrown, but it seems like most of these error messages are statically allocated which makes it harder to change them?

Comment 1 Radar WebKit Bug Importer 2023-05-09 22:32:18 PDT

<rdar://problem/109136179>