Constify trait aliases
Allow `const trait Foo = Bar + [const] Baz;` trait alias declarations. Their rules are the same as with super traits of const traits. So `[const] Baz` or `const Baz` is only required for `[const] Foo` or `const Foo` bounds respectively.
tracking issue rust-lang/rust#41517 (part of the general trait alias feature gate, but I can split it out into a separate const trait alias feature gate. I just assumed that const traits would stabilize before trait aliases, and we'd want to stabilize trait aliases together with const trait aliases at the same time)
r? ``@compiler-errors`` ``@fee1-dead``
Mark desugared range expression spans with DesugaringKind::RangeExpr
This is a prerequisite to removing `QPath::LangItem` (rust-lang/rust#115178) because otherwise there would be no way to detect a range expression in the HIR.
There are some non-obvious Clippy changes so a Clippy team review would be good.
Clairify docs for `AttributeKind::DocComment`
Makes it clear that this represents `#[doc = "content"]`, but not `#[doc(hidden)]` (or other uses of the `#[doc(...)]` attribute).
r? `@jdonszelmann`
interpret `#[used]` as `#[used(compiler)]` on illumos
helps rust-lang/rust#146169 not be as painful: fixes the illumos regression in rust-lang/rust#140872, but `#[used(linker)]` is still erroneous on illumos generally.
illumos' `ld` does not support a flag like either SHF_GNU_RETAIN or SHF_SUNW_NODISCARD, so there is no way to communicate `#[used(linker)]` for that target. Setting `USED_LINKER` to try results in LLVM setting SHF_SUNW_NODISCARD for Solaris-like targets, which is an unknown section header flag for illumos `ld` and prevents sections from being merged that otherwise would.
As a motivating example, the `inventory` crate produces `#[used]` items to merge into `.init_array`. Because those items have an unknown section header flag they are not merged with the default `.init_array` with `frame_dummy`, and end up never executed.
Downgrading `#[used]` to `#[used(compiler)]` on illumos keeps so-attributed items as preserved as they had been before https://github.com/rust-lang/rust/pull/140872. As was the case before that change, because rustc passes `-z ignore` to illumos `ld`, it's possible that `used` sections are GC'd at link time. https://github.com/rust-lang/rust/issues/146169 describes this unfortunate circumstance.
----
as it turns out, `tests/ui/attributes/used_with_archive.rs` had broken on `x86_64-unknown-illumos`, and this patch fixes it. the trials and tribulations of tier 2 :(
r? ````@Noratrieb```` probably?
illumos' `ld` does not support a flag like either SHF_GNU_RETAIN or
SHF_SUNW_NODISCARD, so there is no way to communicate `#[used(linker)]`
for that target. Setting `USED_LINKER` to try results in LLVM setting
SHF_SUNW_NODISCARD for Solaris-like targets, which is an unknown section
header flag for illumos `ld` and prevents sections from being merged
that otherwise would.
As a motivating example, the `inventory` crate produces
`#[used]` items to merge into `.init_array`. Because those items have an
unknown section header flag they are not merged with the default
`.init_array` with `frame_dummy`, and end up never executed.
Downgrading `#[used]` to `#[used(compiler)]` on illumos keeps
so-attributed items as preserved as they had been before
https://github.com/rust-lang/rust/pull/140872. As was the case before
that change, because rustc passes `-z ignore` to illumos `ld`, it's
possible that `used` sections are GC'd at link time.
https://github.com/rust-lang/rust/issues/146169 describes this
unfortunate circumstance.
Use `Iterator::eq` and (dogfood) `eq_by` in compiler and library
Now that rust-lang/rust#137122 has landed, we can replace stuff that looks like:
```rust
let a: &[T];
let b: &[T];
let eq = a.len() == b.len() && a.iter().zip(b).all(|(a,b)| a == b)
```
with the much simpler `a.iter().eq(b)`, without losing the perf benefit of the different-length-fast-path.
Also dogfooded `Iterator::eq_by` (cc rust-lang/rust#64295 ) while I'm at it.
First commit (4d1b6fad230f8a5ccceccc7562eadc4ea50059da) should be very straightforward to review, second one (049a4606cb3906787aedf508ee8eea09c2bb3b9a) is slightly more creative, but IMHO a nice cleanup.
improve diagnostics for empty attributes
Adds a note about them not having any effect. This was previously done for `feature` attributes but no other attributes. In [converting the `feature` parser](https://github.com/rust-lang/rust/pull/146652) I removed that note. This PR adds it back in and makes it so all attributes benefit from it.
Not blocked on rust-lang/rust#146652, either can merge first
Introduce CoerceShared lang item and trait, and basic Reborrow tests
Part of rust-lang/rust#145612: This introduces the `CoerceShared` trait which is the `Reborrow` equivalent of a `&mut T` -> `&T` coercion. The trait has a `Target` GAT which makes this (currently) unique in the `core/src/marker.rs`; I'm not sure if this can be considered problematic. Maybe this is not the way such things should be done at the marker trait level? Or maybe it is fine.
Improtantly, this PR introduces a battery of basic `Reborrow` and `CoerceShared` tests. These test the very basics of the feature; custom marker types intended to have exclusive semantics (`Custom<'a>(PhantomData<&'a mut ()>)`), custom exclusive reference wrappers, and standard library exclusive reference wrappers (`Pin<&mut T>` and `Option<&mut T>`). None of these of course work since the implementation for `Reborrow` and `CoerceShared` is entirely missing, but this is the first step towards making these work.
Future PRs will introduce more tests, such as "recursive" reborrowing (ie. reborrowing structs that contain multiple reborrowable fields) and checks around the lifetime semantics of reborrowing ie. that a reborrow produces a new type with the same lifetime as the original.
Add an attribute to check the number of lanes in a SIMD vector after monomorphization
Allows std::simd to drop the `LaneCount<N>: SupportedLaneCount` trait and maintain good error messages.
Also, extends rust-lang/rust#145967 by including spans in layout errors for all ADTs.
r? ``@RalfJung``
cc ``@workingjubilee`` ``@programmerjake``
initial implementation of the darwin_objc unstable feature
Tracking issue: https://github.com/rust-lang/rust/issues/145496
This feature makes it possible to reference Objective-C classes and selectors using the same ABI used by native Objective-C on Apple/Darwin platforms. Without it, Rust code interacting with Objective-C must resort to loading classes and selectors using costly string-based lookups at runtime. With it, these references can be loaded efficiently at dynamic load time.
r? ```@tmandry```
try-job: `*apple*`
try-job: `x86_64-gnu-nopt`
Migrate `UnsizedConstParamTy` to unstable impl of `ConstParamTy_`
Now that we have ``#[unstable_feature_bound]``, we can remove ``UnsizedConstParamTy`` that was meant to be an unstable impl of stable type and ``ConstParamTy_`` trait.
r? `@BoxyUwU`
Make `AssocItem` aware of its impl kind
The general goal is to have fewer query dependencies by making `AssocItem` aware of its parent impl kind (inherent vs. trait) without having to query the parent def_kind.
See individual commits.
Convert `no_std` and `no_core` to the new attribute infrastructure
r? ```@oli-obk```
Also added a test for these, since we didn't have any and I was kind of surprised new diagnostics didn't break anything hehe
Skip typeck for items w/o their own typeck context
Skip items which forward typeck to their ancestor.
Should remove some potential but unnecessary typeck query waits, hence might improve performance for the parallel frontend.
Thanks to `@ywxt` for a fix suggestion
Fixesrust-lang/rust#141951
