Removes unnecessary allocates and double-sorting the same vector,
makes the code a little nicer.

When encountering code like `f::<f::<f::<f::<f::<f::<f::<f::<...` with
unmatched closing angle brackets, add a linear check that avoids the
exponential behavior of the parse recovery mechanism.

Fix rust-lang#117080.

This field allows SMIR consumers to identify which locals correspond to
argument locals. It simply exposes the arg_count field from the MIR
representation.

This commit hides the arg_count field in Body and instead exposes more
stable and user-friendly methods to get the return and argument locals.
As a result, Body instances must now be constructed using the `new`
function.

This is particularly helpful for the ui tests, but also could be helpful
for Stable MIR users who just want all the locals without needing to
concatenate responses

I.e. in the source file where it's used.

The word internal has connotations about information that's not exposed.
It's more accurate to say that the remaining locals apply only to the
inner part of the function, so I'm renaming them to inner locals.

The latest locals() method in stable MIR returns slices instead of vecs.
This commit also includes fixes to the existing tests that previously
referenced the private locals field.

Not using this flag is identical to passing `-Cinstrument-coverage=off`, so
there's no need to distinguish between `None` and `Some(Off)`.

This reverts commit 8e06b25.

…=petrochenkov

refactor(compiler/resolve): simplify some code

Removes unnecessary allocate and double-sorting the same vector, makes the code a little nicer.

Add way to differentiate argument locals from other locals in Stable MIR

This PR resolves rust-lang/project-stable-mir#47 which request a way to differentiate argument locals in a SMIR `Body` from other locals.

Specifically, this PR exposes the `arg_count` field from the MIR `Body`. However, I'm opening this as a draft PR because I think there are a few outstanding questions on how this information should be exposed and described. Namely:

- Is exposing `arg_count` the best way to surface this information to SMIR users? Would it be better to leave `arg_count` as a private field and add public methods (e.g. `fn arguments(&self) -> Iter<'_, LocalDecls>`) that may use the underlying `arg_count` info from the MIR body, but expose this information to users in a more convenient form? Or is it best to stick close to the current MIR convention?
- If the answer to the above point is to stick with the current MIR convention (`arg_count`), is it reasonable to also commit to sticking to the current MIR convention that the first local is always the return local, while the next `arg_count` locals are always the (in-order) argument locals?
- Should `Body` in SMIR only represent function bodies (as implied by the comment I added)? That seems to be the current case in MIR, but should this restriction always be the case for SMIR?

r? `@celinval`
r? `@oli-obk`

Avoid unbounded O(n^2) when parsing nested type args

When encountering code like `f::<f::<f::<f::<f::<f::<f::<f::<...` with unmatched closing angle brackets, add a linear check that avoids the exponential behavior of the parse recovery mechanism.

Fix rust-lang#117080, fix rust-lang#115414.

…jgillot

Minor improvements to `rustc_incremental`

Just some things I spotted while looking at this code.

r? `@cjgillot`

…-reviewers, r=Nilstrieb

Revert "Remove TaKO8Ki from reviewers"

ref rust-lang#116061

It's been a month since this pull request, and I now have some available time for reviews. Would it be okay to revisit it as a reviewer?

This reverts commit 8e06b25.

r? `@Nilstrieb`

The value of `-Cinstrument-coverage=` doesn't need to be `Option`

(Extracted from rust-lang#117199, since this is a purely internal cleanup that can land independently.)

Not using this flag is identical to passing `-Cinstrument-coverage=off`, so there's no need to distinguish between `None` and `Some(Off)`.

…ler-errors

Quietly fail if an error has already occurred

fixes rust-lang#117195

…to-COROUTINE, r=lqd

Rename type flag `HAS_TY_GENERATOR` to `HAS_TY_COROUTINE`

r? oli-obk