…iaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#127669 (Fix the issue of invalid suggestion for a reference of iterator)
 - rust-lang#127707 (match lowering: Use an iterator to find `expand_until`)
 - rust-lang#127730 (Fix and enforce `unsafe_op_in_unsafe_fn` in compiler)
 - rust-lang#127789 (delete #![allow(unsafe_op_in_unsafe_fn)] in teeos)
 - rust-lang#127805 (run-make-support: update gimli to 0.31.0)
 - rust-lang#127808 (Make ErrorGuaranteed discoverable outside types, consts, and lifetimes)
 - rust-lang#127817 (Fix a bunch of sites that were walking instead of visiting, making it impossible for visitor impls to look at these values)
 - rust-lang#127818 (Various ast validation simplifications)

r? `@ghost`
`@rustbot` modify labels: rollup

Rollup merge of rust-lang#127808 - oli-obk:tainting_visitors2, r=lcnr,nnethercote

Make ErrorGuaranteed discoverable outside types, consts, and lifetimes

types like `PatKind` could contain `ErrorGuaranteed`, but not return them via `tainted_by_errors` or `error_reported` (see rust-lang#127687 (comment)). Now this happens, but it's a bit fragile as you can see with the `TypeSuperVisitable for Ty` impl.

We will catch any problems around Ty, Region or Const at runtime with an assert, and everything using derives will not have such issues, as it will just invoke the `TypeVisitable for ErrorGuaranteed` impl