Fixes rust-lang#78192

Fixes rust-lang#42474.

…stions

and improve a comment a bit

Co-authored-by: BlackHoleFox <blackholefoxdev@gmail.com>

…ner; we no longer need the ignore_interior_mut_in_const hack

Tweak match arm semicolon removal suggestion to account for futures

* Tweak and extend "use `.await`" suggestions
* Suggest removal of semicolon on prior match arm
* Account for `impl Future` when suggesting semicolon removal
* Silence some errors when encountering `await foo()?` as can't be certain what the intent was

*Thanks to https://twitter.com/a_hoverbear/status/1318960787105353728 for pointing this out!*

…, r=m-ou-se

Capture output from threads spawned in tests

This is revival of rust-lang#75172.

Original text:
> Fixes rust-lang#42474.
>
> r? `@dtolnay` since you expressed interest in this, but feel free to redirect if you aren't the right person anymore.

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Closes rust-lang#75172.

Fix rust-lang#78192

Check which places are marked dead.

Fixes rust-lang#78192

Do not try to report on closures to avoid ICE

Fixes rust-lang#78262

…-obk

ensure that statics are inhabited

Fixes rust-lang#74840

r? @oli-obk

Make some functions private that don't have to be public

r? @GuillaumeGomez

…i-obk

Move "mutable thing in const" check from interning to validity

This moves the check for mutable things (such as `UnsafeCell` or `&mut`) in a`const` from interning to validity. That means we can give more targeted error messages (pointing out *where* the problem lies), and we can simplify interning a bit.

Also fix the interning mode used for promoteds in statics.

r? @oli-obk