Rustdoc displays negative impls for traits identically to standard impls

[mkovalchik]

When documenting negative impls for the Send and Sync traits (added by RFC 19) rustdoc currently displays the negative impls identically to positive impls.

As an example, there's currently no indication that the Send impl for MutexGuard is actually opting out of the Send trait rather than adding an implementation of it.

[kmcallister]

Eek.

[sellibitze]

It seems the issue has not been solved completely. On a trait's page that lists all its implementors, it's still wrong. Checkout http://doc.rust-lang.org/std/marker/trait.Send.html for example.

[steveklabnik]

@sellibitze you mentioned http://doc.rust-lang.org/std/rc/struct.Rc.html in IRC, but I'm clearly seeing !Send: http://doc.rust-lang.org/std/rc/struct.Rc.html

[steveklabnik]

After further discussion, http://doc.rust-lang.org/std/marker/trait.Send.html is still not showing !.

[sellibitze]

Maybe the right thing to do is to just not mention Rc on trait.Send at all. Either that, or adding a '!' in there.

[Diggsey]

Or add the "!", but show them in a separate section below.

[pnkfelix]

1.0 polish, "P-veryhigh"