- Make the structure of the two variants more similar.
- Add some comments.
- Move various conditional `use` items inside the function that uses
  them.
- Inline some closures.

It took me a while to work this out.

…s input vs output

Fix `SelfVisitor::is_self_ty` ICE

Fixes rust-lang#103202

Clarify startup

A small follow-up to rust-lang#102769.

r? `@jyn514`

Adjust `transmute{,_copy}` to be clearer about which of `T` and `U` is input vs output

This is essentially a documentation-only change (although it does touch code in an irrelevant way).

Fixed docs typo in `library/std/src/time.rs`

* Changed comment from `Previous rust versions panicked when self was earlier than the current time.` to `Previous rust versions panicked when the current time was earlier than self.`
* Resolves rust-lang#103282.

…rtcuts, r=notriddle

+/- shortcut now only expand/collapse, not both

Fixes rust-lang#102772.

r? ```@notriddle```

fix typo

Don't label `src/test` tests as `A-testsuite`

Nearly every PR modifies `src/test`; A-testsuite is meant to be for things affecting the test runners themselves.

cc rust-lang#103204 (comment)

r? `@jyn514`

…r=bjorn3

interpret: remove an incorrect assertion

This fixes an ICE in Miri, [reported](https://rust-lang.zulipchat.com/#narrow/stream/269128-miri/topic/SwitchInt.20with.20no.20targets.3F) by `@saethlin.` The faulty assertion was introduced by rust-lang@432535d, when a previously correct assertion checking that the `otherwise` target exists got replaced by this assertion checking that at least one more target beyond `otherwise` exists.

Sadly we don't have a small reproducer so I don't think we can easily add a testcase.

…nst_msg, r=oli-obk

Improve "`~const` is not allowed here" message

r? `@oli-obk`