Some tests took too long and owning_ref is fundamentally flawed,
so don't run these tests or run them with a shorter N. This makes
miri with `-Zmiri-strict-provenance` usable to find UB.

It creates the src pointer first, which is then invalidated by a
unique borrow of the destination pointer. Swap the borrows around
to fix this. Found with miri.

Hack: many traits and types in std are re-exported from core or alloc. In
general, rustdoc is capable of recognizing these implementations as being
on local types. However, in at least one case, rustdoc gets confused and
labels an implementation as being on a foreign type. To make sure that
confusion doesn't pass on to the reader, consider all implementations in
std, core, and alloc to be on local types.

…ports

…r, r=cjgillot

Iterate over `maybe_unused_trait_imports` when checking dead trait imports

Closes rust-lang#96873
r? `@cjgillot`

Some questions, if you have time:

- Is there a way to shorten the `rustc_data_structures::fx::FxIndexSet` path in the query declaration? I wasn't sure where to put a `use`.
- Was returning by reference from the query the right choice here?
- How would I go about evaluating the importance of the `is_dummy()` call in `check_crate`? I don't see failing tests when I comment it out. Should I just try to determine whether dummy spans can ever be put into `maybe_unused_trait_imports`?
- Am I doing anything silly with the various ID types?
- Is that `let-else` with `unreachable!()` bad? (i.e is there a better idiom? Would `panic!("<explanation>")` be better?)
- If I want to evaluate the perf of using a `Vec` as mentioned in rust-lang#96873, is the best way to use the CI or is it feasible locally?

Thanks :)

…ulacrum

test const_copy to make sure bytewise pointer copies are working

This is non-trivial; for `swap_nonoverlapping`, this is [not working](rust-lang#83163 (comment)).

…illot

Improve soundness of rustc_data_structures

Make it runnable in miri by adding some ignores and changing N in miri. Also fix a stacked borrows issue in sip128.

…rrors

Add regresion test for rust-lang#87142

Closes rust-lang#87142
r? `@compiler-errors`

Don't generate "Impls on Foreign Types" for std

Hack: many traits and types in std are re-exported from core or alloc. In general, rustdoc is capable of recognizing these implementations as being on local types. However, in at least one case, rustdoc gets confused and labels an implementation as being on a foreign type. To make sure that confusion doesn't pass on to the reader, consider all implementations in std, core, and alloc to be on local types.

Demo: https://rustdoc.crud.net/jsha/no-foreign-std/std/clone/trait.Clone.html

…x, r=compiler-errors

Fix pretty printing named bound regions under -Zverbose

Fixed regression introduced in rust-lang#97023

r? `@compiler-errors`

cc `@cjgillot`