…matthewjasper

Fix regression in the MIR lowering of or-patterns

In rust-lang#126553 I made a silly indexing mistake and regressed the MIR lowering of or-patterns. This fixes it.

r? `@compiler-errors` because I'd like this to be merged quickly 🙏

…iaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#127028 (Fix regression in the MIR lowering of or-patterns)
 - rust-lang#127091 (impl FusedIterator and a size hint for the error sources iter)
 - rust-lang#127358 (Automatically taint when reporting errors from ItemCtxt)
 - rust-lang#127382 (Use verbose style when suggesting changing `const` with `let`)
 - rust-lang#127397 (fix interleaved output in the default panic hook when multiple threads panic simultaneously)
 - rust-lang#127484 (`#[doc(alias)]`'s doc: say that ASCII spaces are allowed)
 - rust-lang#127496 (Update `f16`/`f128` FIXMEs that needed `(NEG_)INFINITY`)
 - rust-lang#127508 (small search graph refactor)

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

…atthewjasper

match lowering: Clarify the main loop of the algorithm

Now that we expand or-patterns in a single place in the algorithm, we can move it (back) to the main part of the loop. This makes the call-graph of the main loop rather simple: `match_candidates` has three branches that each call back to `match_candidates`. The remaining tricky part is `finalize_or_candidate`.

I also factored out the whole "process a prefix of the candidates then process the rest" thing which I think helps legibility.

The first two commits are a fix for an indexing mistake I introduced in rust-lang#126553, already sumitted in rust-lang#127028 but feel free to merge this first.

r? `@matthewjasper`

Rollup merge of rust-lang#127164 - Nadrieril:clean-lowering-loop, r=matthewjasper

match lowering: Clarify the main loop of the algorithm

Now that we expand or-patterns in a single place in the algorithm, we can move it (back) to the main part of the loop. This makes the call-graph of the main loop rather simple: `match_candidates` has three branches that each call back to `match_candidates`. The remaining tricky part is `finalize_or_candidate`.

I also factored out the whole "process a prefix of the candidates then process the rest" thing which I think helps legibility.

The first two commits are a fix for an indexing mistake I introduced in rust-lang#126553, already sumitted in rust-lang#127028 but feel free to merge this first.

r? `@matthewjasper`