Bug 142774 – Enable ES6 classes by default

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Ryosuke Niwa]

Now that default constructor is supported, we're ready for the prime time!

[Ryosuke Niwa]

Created attachment 248814 [details]
Enables the feature

[Ryosuke Niwa]

Created attachment 248815 [details]
Fixed double ChangeLog

[Ryosuke Niwa]

Thanks for the review!

[Ryosuke Niwa]

Committed r181618: <http://trac.webkit.org/changeset/181618>

[Joseph Pecoraro]

Comment on attachment 248815 [details]
Fixed double ChangeLog

View in context: https://bugs.webkit.org/attachment.cgi?id=248815&action=review

> LayoutTests/js/script-tests/class-syntax-super.js:55
> -shouldThrow('new (class extends Base { constructor() { } })', '"TypeError: Cannot return a non-object type in the constructor of a derived class."');
> +shouldThrow('new (class extends Base { constructor() { } })', '"ReferenceError: Cannot access uninitialized variable."');

This error message can certainly be improved. I don't see what is wrong here. Is it a missing call to super()?

[Ryosuke Niwa]

(In reply to comment #5)
> Comment on attachment 248815 [details]
> Fixed double ChangeLog
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=248815&action=review
> 
> > LayoutTests/js/script-tests/class-syntax-super.js:55
> > -shouldThrow('new (class extends Base { constructor() { } })', '"TypeError: Cannot return a non-object type in the constructor of a derived class."');
> > +shouldThrow('new (class extends Base { constructor() { } })', '"ReferenceError: Cannot access uninitialized variable."');
> 
> This error message can certainly be improved. I don't see what is wrong
> here. Is it a missing call to super()?

Yes. The problem here is that constructor() {} doesn't initialize "this" so we can't return safely.