rust/compiler/rustc_hir/src, branch master

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

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

2025-09-22T04:30:16+00:00

Port #[macro_export] to the new attribute parsing infrastructure

2025-09-21T14:42:47+00:00

Co-authored-by: Anne Stijns