Bug 275143 – ReferenceError doesn't include variable name in error message

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Jarred Sumner]

`ReferenceError` in JSC does not include the variable name.


If we run the following in `jsc`:

```
❯ jsc -e 'const fetch = fetch("https://example.com")'
Exception: ReferenceError: Cannot access uninitialized variable.
global code@[Command Line]:1:20
```

If the run the following in `node`:
```
❯ node -e 'const fetch = fetch("https://example.com")'
// ...
ReferenceError: Cannot access 'fetch' before initialization
```

If we run the same code in Firefox:
```
Uncaught ReferenceError: can't access lexical declaration 'fetch' before initialization
```

Of these, JavaScriptCore is the only one which does not include the variable name in ReferenceError.

We've addressed this in bun's WebKit fork here: https://github.com/oven-sh/WebKit/pull/56/files. If it's helpful, feel free to use the code. There's probably a better way to do it where it passes the identifier via the property offset of the target and avoids heap-allocating a JSString but I'm not totally sure

[Radar WebKit Bug Importer]

<rdar://problem/129659300>

Pull request: https://github.com/WebKit/WebKit/pull/48153

[EWS]

Committed 300119@main (412a6c047fa6): <https://commits.webkit.org/300119@main>

Reviewed commits have been landed. Closing PR #48153 and removing active labels.