Deny capturing late-bound ty/const params in nested opaques
First, this reverts a7f609504c. I can't exactly remember why I approved this specific bit of https://github.com/rust-lang/rust/pull/132466; specifically, I don't know that the purpose of that commit is, and afaict we will never have an opaque that captures late-bound params through a const because opaques can't be used inside of anon consts. Am I missing something `@cjgillot?` Since I can't see a case where this matters, and no tests seem to fail.
The second commit adds a `deny_late_regions: bool` to distinguish `Scope::LateBoundary` which should deny *any* late-bound params or just ty/consts. Then, when resolving opaques we wrap ourselves in a `Scope::LateBoundary { deny_late_regions: false }` so that we deny late-bound ty/const, which fixes a bunch of ICEs that all vaguely look like `impl for<T> Trait<Assoc = impl OtherTrait<T>>`.
I guess this could be achieved other ways; for example, with a different scope kind, or maybe we could just reuse `Scope::Opaque`. But this seems a bit more verbose. I'm open to feedback anyways.
Fixes#131535Fixes#131637Fixes#132530
I opted to remove those crashes tests ^ without adding them as regular tests, since they're basically triggering uninteresting late-bound ICEs far off in the trait solver, and the reason that existing tests such as `tests/ui/type-alias-impl-trait/non-lifetime-binder-in-constraint.rs` don't ICE are kinda just coincidental (i.e. due to a missing impl block). I don't really feel motivated to add random permutations to tests just to exercise non-lifetime binders.
r? cjgillot
a1c98ca160