…come from impls

…s own span

This accomplishes something like 16a4ad7,
but with the `rustc_allowed_through_unstable_modules` attribute instead
of the path length.

…er-errors

remove unnecessary `eval_verify_bound`

This does not impact any tests. I feel like any cases where this could useful should instead be fixed by a general improvement to `eval_verify_bound` to avoid having to promote this `TypeTest` in the first place 🤔

r? types cc ``@nikomatsakis``

…-typeck, r=BoxyUwU

Normalize each signature input/output in `typeck_with_fallback` with its own span

Applies the same hack as rust-lang#106582 but to the args in typeck. Greatly improves normalization error spans from a signature.

…r=oli-obk

Lower Guard Patterns to HIR.

Implements lowering of [guard patterns](https://rust-lang.github.io/rfcs/3637-guard-patterns.html) (see the [tracking issue](rust-lang#129967)) to HIR.

Use a post-monomorphization typing env when mangling components that come from impls

When mangling associated methods of impls, we were previously using the wrong param-env. Instead of using a fully monomorphized param-env like we usually do in codegen, we were taking the post-analysis param-env, and treating it as an early binder to *re-substitute* the impl args. I've pointed out the problematic old code in an inline comment.

This would give us param-envs with possibly trivial predicates that would prevent normalization via param-env shadowing.

In the example test linked below, `tests/ui/symbol-names/normalize-in-param-env.rs`, this happens when we mangle the impl `impl<P: Point2> MyFrom<P::S> for P` with the substitution `P = Vec2`. Because the where clause of the impl is `P: Point2`, which elaborates to `[P: Point2, P: Point, <P as Point>::S projects-to <P as Point2>::S2]` and the fact that `impl Point2 for Vec2` normalizes `Vec2::S2` to `Vec2::S`, this causes a cycle.

The proper fix here is to use a fully monomorphized param-env for the case where the impl is properly substituted.

Fixes rust-lang#135143

While rust-lang#134081 uncovered this bug for legacy symbol mangling, it was preexisting for v0 symbol mangling. This PR fixes both. The test requires a "hack" because we strip the args of the instance we're printing for legacy symbol mangling except for drop glue, so we box a closure to ensure we generate drop glue.

r? oli-obk

…-better, r=GuillaumeGomez

rustdoc: use stable paths as preferred canonical paths

This accomplishes something like 16a4ad7, but with the `rustc_allowed_through_unstable_modules` attribute instead of the path length.

Fixes rust-lang#131676

…r=ytmimi,compiler-errors

rustfmt: drop nightly-gating of the `--style-edition` flag registration

Follow-up to [Stabilize `style_edition = "2024"` in-tree rust-lang#134929](rust-lang#134929).

rust-lang#134929 un-nightly-gated the *read* of `--style-edition`, but didn't also un-nightly-gate the *registration*/*declaration* of the `--style-edition` flag itself. Reading `--style-edition` on a non-nightly channel (e.g. beta) will thus panic because `--style-edition` is never declared.

This PR also un-nightly-gates the registration. Not sure how to write a regression test for this, because this *requires* the non-nightly / beta channel. Though existing tests do fail (albeit indirectly).

Checking if this fixes the panic against beta in rust-lang#135197.

r? rustfmt