Rustdoc incorrectly orders trait impls

[ghost]

Documentation for Rc: https://doc.rust-lang.org/nightly/std/rc/struct.Rc.html
Source code: https://doc.rust-lang.org/nightly/src/alloc/rc.rs.html#263-265

In the source impls for !Send and !Sync come one after another. In the generated documentation they don't.

The docs should respect the order of impls in the source - that's what I've been told in the #rust-docs channel. In fact, other impls for Rc apparently don't follow the order from the source either. What order do they follow? :)

[jyn514]

Triage: on nightly, these now happen to match the source order, but I think because they're in alphabetical order, not because rustdoc is trying to match the original order; Borrow is shown after AsRef even though it comes earlier in source order.

Matching source order seems useful to me, but conflicts with #51129. Maybe we should give sorting Trait and !Trait precedence, and then sort by source order after that? Sorting by alphabetical order also seems reasonable, though.

[hkBst]

What is the situation here?