Stabilize slice_sort_by_cached_key
I was going to ask on the tracking issue (https://github.com/rust-lang/rust/issues/34447), but decided to just send this and hope for an FCP here. The method was added last March by https://github.com/rust-lang/rust/pull/48639.
Signature: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_by_cached_key
```rust
impl [T] {
pub fn sort_by_cached_key<K, F>(&mut self, f: F)
where F: FnMut(&T) -> K, K: Ord;
}
```
That's an identical signature to the existing `sort_by_key`, so I think the questions are just naming, implementation, and the usual "do we want this?".
The implementation seems to have proven its use in rustc at least, which many uses: https://github.com/rust-lang/rust/search?l=Rust&q=sort_by_cached_key
(I'm asking because it's exactly what I just needed the other day:
```rust
all_positions.sort_by_cached_key(|&n|
data::CITIES.iter()
.map(|x| *metric_closure.get_edge(n, x.pos).unwrap())
.sum::<usize>()
);
```
since caching that key is a pretty obviously good idea.)
Closes#34447
Rename rustc_errors dependency in rust 2018 crates
I think this is a better solution than `use rustc_errors as errors` in `lib.rs` and `use crate::errors` in modules.
Related: rust-lang/cargo#5653
cc #58099
r? @Centril
Cosmetic improvements to doc comments
This has been factored out from https://github.com/rust-lang/rust/pull/58036 to only include changes to documentation comments (throughout the rustc codebase).
r? @steveklabnik
Once you're happy with this, maybe we could get it through with r=1, so it doesn't constantly get invalidated? (I'm not sure this will be an issue, but just in case...) Anyway, thanks for your advice so far!
Require a list of features in `#[allow_internal_unstable]`
The blanket-permission slip is not great and will likely give us trouble some point down the road.
while we could make this change (it's all unstable after all), there are crates.io crates that use the feature and that the compiler depends upon. We can instead roll out this feature while still supporting the old way.
Deduplicate mismatched delimiter errors
Delay unmatched delimiter errors until after the parser has run to deduplicate them when parsing and attempt recovering intelligently.
Second attempt at #54029, follow up to #53949. Fix#31528.
Error on duplicate matcher bindings
fix #57593
This should not be merged without a crater run and maybe an FCP. Discussion is ongoing at #57593.
TODO:
- [x] write tests
- [x] crater run
- [x] ~maybe need edition gating?~ not for 1 regression /centril
r? @petrochenkov
Add const generics to the AST
This is mostly split out from https://github.com/rust-lang/rust/pull/53645 in an effort to make progress merging const generics piecewise instead of in one go.
cc @yodaldevoid, @petrochenkov
r? @eddyb
Mazdak Farrokhzad