Tracking issue for RFC 490 - DST syntax changes

[nrc]

Change Sized? T to T: ?Sized and trait T for Sized? to trait T for ?Sized.

Nominated because backwards incompatible - lang

[nrc]

RFC: https://github.com/rust-lang/rfcs/blob/master/text/0490-dst-syntax.md

[nrc]

Happy to mentor this if anyone wants to do it. It requires some changes to the parser and then a bunch of cleanup of libraries etc. Probably the easiest way to handle the fallout will be to accept both the old and new forms and remove the old form after a snapshot.

[nrc]

I've assigned myself so I don't forget this, but I'm happy if anyone wants to take this.

[tomjakubowski]

The syntax in the OP (T ?Sized) seems to disagree with the syntax in the RFC (T: ?Sized), which one is it?

Also, a gentle reminder that rustdoc should be updated to render the new syntax too!

[nrc]

The RFC is right (and I've updated the OP).

[brson]

1.0 P-backcompat-lang