rust/compiler/rustc_hir/src, branch auto

Rollup merge of #147117 - iximeow:ixi/illumos-used-attr, r=Noratrieb

2025-10-04T10:31:27+00:00

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?

interpret #[used] as #[used(compiler)] on illumos

2025-10-03T22:03:24+00:00

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.

Rollup merge of #147101 - yotamofek:pr/iter-eq-and-eq-by, r=jdonszelmann

2025-09-29T11:06:45+00:00

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.

Rollup merge of #146653 - jdonszelmann:empty-attr-diags, r=nnethercote

2025-09-29T11:06:44+00:00

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

Use `Iterator::eq` and (dogfood) `eq_by` in compiler and library

2025-09-29T05:08:05+00:00

Rollup merge of #146037 - aapoalas:reborrow-lang-experiment, r=tmandry

2025-09-27T19:25:56+00:00

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.

improve empty attribute diagnostic

2025-09-27T17:32:14+00:00

Rollup merge of #146704 - jdonszelmann:port-debug-visualizer, r=petrochenkov

2025-09-26T16:11:09+00:00

port `#[debugger_visualizer]` to the new attribute system

Rollup merge of #146667 - calebzulawski:simd-mono-lane-limit, r=lcnr,RalfJung

2025-09-25T10:31:53+00:00

Add an attribute to check the number of lanes in a SIMD vector after monomorphization Allows std::simd to drop the `LaneCount: 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``

Add an attribute to check the number of lanes in a SIMD vector after monomorphization

2025-09-24T00:47:34+00:00

Unify zero-length and oversized SIMD errors