Since there is nothing to optimise there...

Make `Unique::as_ptr` const without feature attribute as it's unstable
Make `NonNull::dangling` and `NonNull::cast` const with `feature = "const_ptr_nonnull"`

Co-Authored-By: RalfJung <post@ralfj.de>

…oerister

Use informational target machine for metadata

Since there is nothing to optimise there...

Should fix rust-lang#58323 but haven’t tested locally.

r? @michaelwoerister

rust-lldb: fix crash when printing empty string

Fixes rust-lang#52185.

~Re-enables the pretty-std debuginfo test and tweaks the test as necessary to get it to pass again. This reveals that lldb's formatting of enums is broken (rust-lang#58492). I also removed the emoji from the test because I couldn't get the docker image's gdb to print the emoji, just octal escapes (https://github.com/rust-lang/rust/pull/53154/files#r208263904).~

…scottmcm

Have all methods of Filter and FilterMap use internal iteration

This PR changes `Filter::{next, next_back, count}` and `FilterMap::{next, next_back}` to all use internal iteration. The `next` and `next_back` methods are changed to directly forward to `try_for_each` and `try_rfold` respectively, using `Result` as the `Try` type. I think that's okay? Alternatively, I could change their implementations to use `LoopState` instead if there's any benefit in doing so.

r? @scottmcm

…hton

Add tests for several E-needstest issues

This PR adds a number of tests for various `E-needstest` errors. These tend to have been left open for a long time and seem unlikely to be closed otherwise.

Closes rust-lang#10876.
Closes rust-lang#22892.
Closes rust-lang#26448.
Closes rust-lang#26577.
Closes rust-lang#26619.
Closes rust-lang#27054.
Closes rust-lang#28587.
Closes rust-lang#44127.
Closes rust-lang#44255.
Closes rust-lang#55731.
Closes rust-lang#57781.

Make `Unique::as_ptr`, `NonNull::dangling` and `NonNull::cast` const

ManuallyDrop != MaybeUninit

Cc @Centril

Replace `s` with `self` in docs for str methods taking self.

Cherry picked from PR rust-lang#58596 which is blocked on some intra-doc link bugs.

allow specifying attributes for tool lints

Needed for clippy to fix `unused_doc_comments` warnings that will be exposed by rust-lang#57882 (and thus unblock it).

…nkfelix

Make migrate mode work at item level granularity

Migrate mode now works entirely at the item level rather than the body level,
ensuring that we don't lose any errors in contained closures.

Closes rust-lang#58776

r? @pnkfelix

Fixed a syntax error in the pin docs

…i-obk

tidy: deny(rust_2018_idioms)

r? @oli-obk