…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#127818 - oli-obk:ast_validation_simplifications, r=petrochenkov

Various ast validation simplifications

Changes pulled out of rust-lang#127524

These are needed to make ast validation a mutable visitor, as we can't keep immutable references to the AST around in that case. But I think they are simplifying things in general and can stand on their own