closes: rust-lang#98070

- require `TypeErrCtxt` to always result in an error
- move `resolve_regions_and_report_errors` to the `ObligationCtxt`
- merge `process_registered_region_obligations` into `resolve_regions`

Typo in the documentation.

It's what all the call sites require.

It's weird and unnecessary.

It is only implemented for `Region`, where it is equivalent to the
inherent `as_var` method.

I'm surprised the compiler doesn't warn about these. It appears having
an `impl` on a struct is enough to avoid a warning about it never being
constructed.

…, r=Mark-Simulacrum

Stabilize IsTerminal

FCP completed in rust-lang#98070 .

closes: rust-lang#98070

…iemjay

Erase lifetimes above `ty::INNERMOST` when probing ambiguous types

Turns out that `TyCtxt::replace_escaping_bound_vars_uncached` only erases bound vars exactly at `ty::INNERMOST`, and not everything above. This regresses the suggestions for non-lifetime binders, but oh well, I don't really care about those.

Fixes rust-lang#110052

…iler-errors

Remove `ToRegionVid`

r? ```@compiler-errors```

cleanup our region error API

- require `TypeErrCtxt` to always result in an error, closing rust-lang#108810
- move `resolve_regions_and_report_errors` to the `ObligationCtxt`
- call `process_registered_region_obligations` in `resolve_regions`
- move `resolve_regions` into the `outlives` submodule
- add `#[must_use]` to functions returning lists of errors

r? types

…=cuviper

Fix btree `CursorMut::insert_after` check

Fixes a check inside `BTreeMap`'s `CursorMut::insert_after`, where it would peek the previous element to check whether the inserted key is below the next one, instead of peeking the next element.

Update unwind_safe.rs

Typo in the documentation.