Bug 170174 – ES2015 modules - Export default function hoisting

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Guy Bedford]

The following circular reference case should work as export default can be used with function declarations that are hoisted, according to the rules of the HoistableDeclaration lookahead (https://tc39.github.io/ecma262/#prod-HoistableDeclaration).

Instead, Safari gives the following error: SyntaxError: Importing binding name 'a' is not found.

a.js:
```
import b from './b.js';

b();

export default function a () {
  console.log('a');
}
```

b.js:
```
import a from './a.js';

export default function b () {
  a();
}
```

Where a `<script type="module" src="a.js"></script>` is included in the page.

This can be verified to work in the named exports hoisting case by converting the example to use `export function a ()`, `import {a}`, etc.

[Guy Bedford]

Updated link to the "export default HoistableDeclaration" rule - https://tc39.github.io/ecma262/#prod-ExportDeclaration.

[Yusuke Suzuki]

Yeah, this bug is now fixed by fixing hoisting rules in JSC.
I'll add this specific test into JSC's module tests :D

[Yusuke Suzuki]

Created attachment 311812 [details]
Patch

[Guy Bedford]

Great to heat that! The tests could be mixed together to form Mocha tests though :P

[Yusuke Suzuki]

Comment on attachment 311812 [details]
Patch

Thanks ;)

[Yusuke Suzuki]

(In reply to Guy Bedford from comment #4)
> Great to heat that! The tests could be mixed together to form Mocha tests
> though :P

Mocha is also one of my favorite drink ;)

[WebKit Commit Bot]

Comment on attachment 311812 [details]
Patch

Clearing flags on attachment: 311812

Committed r217747: <http://trac.webkit.org/changeset/217747>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.