Update books
## rust-embedded/book
1 commits in e88aa4403b4bf2071c8df9509160477e40179099..2463edeb8003c5743918b3739a9f6870b86396f5
2026-03-11 17:49:58 UTC to 2026-03-11 17:49:58 UTC
- Update teaching material duration for bare-metal Rust (rust-embedded/book#409)
## rust-lang/reference
7 commits in c49e89cc8c7c2c43ca625a8d5b7ad9a53a9ce978..7446bf9697c95d155eef33c6a9d91fbd29a5e359
2026-03-18 01:46:01 UTC to 2026-03-10 18:10:22 UTC
- Update `must_use` to use the attribute template (rust-lang/reference#1892)
- Add a rule that enum discriminants may not use generic parameters (rust-lang/reference#2206)
- Actually move out of Box in moving-out-of-Box test (rust-lang/reference#2204)
- Add special cases and links relating to dereferencing boxes (rust-lang/reference#2075)
- Move shebang into its own subchapter (rust-lang/reference#2199)
- Fields of enums and unions should be allowed to overlap (rust-lang/reference#2168)
- [type layout] Clarify size and alignment of pointers to unsized types (rust-lang/reference#2201)
Fix invalid add of duplicated call locations for the rustdoc scraped examples feature
Fixesrust-lang/rust#153837.
The bug was visible in the highlighting of the scrape examples code samples: the same part of the code was marked as "highlight" (by the scraped examples feature) twice, eventually leading to a wrong state of the HTML DOM status.
To fix the bug, I added a set to not re-add a location if it's already present.
r? @Urgau
Fix `doc_cfg` not working as expected on trait impls
Fixes https://github.com/rust-lang/rust/issues/153655.
I spent waaaaay too much time on this fix. So the current issue is that rustdoc gets its items in two passes:
1. All items
2. Trait/blanket/auto impls
Because of that, the trait impls are not stored "correctly" in the rustdoc AST, meaning that the `propagate_doc_cfg` pass doesn't work correctly on them. So initially, I tried to "clean" the impls at the same time as the other items. However, it created a monstruous amount of bugs and issues and after two days, I decided to give up on this approach (might be worth fixing that in the future!). You can see what I tried [here](https://github.com/rust-lang/rust/compare/main...GuillaumeGomez:trait-impls-doc_cfg?expand=1).
So instead, since the impls are stored at the end, I create placeholders for impls and in `propagate_doc_cfg`, I store the `cfg` "context" (more clear when reading the code 😛) and re-use it later on when the "real" impl comes up.
r? @lolbinarycat
Allow applying autodiff macros to trait functions.
It will use enzyme to generate a default derivative implementation, which can be overwritten by the user.
closes: https://github.com/rust-lang/rust/issues/153329
r? @JonathanBrouwer
tests/ui/async-await/gat-is-send-across-await.rs: New regression test
The test began passing in `nightly-2025-10-16`. Probably by c50aebba78 (rust-lang/rust#144064) because it fixed two "does not live long enough" errors. The test fails to compile with `nightly-2025-10-15` with such an error:
$ rustc +nightly-2025-10-15 --edition 2018 tests/ui/async-await/gat-is-send-across-await.rs
error: `impl G` does not live long enough
--> tests/ui/async-await/gat-is-send-across-await.rs:16:24
|
16 | let _: &dyn Send = &async move {
| ________________________^
17 | | let _gat = g.as_gat();
18 | | async{}.await
19 | | };
| |_____^
Closesrust-lang/rust#111852 since that's where the test comes from.
const validity checking: do not recurse to references inside MaybeDangling
This arguably should be allowed, but we currently reject it:
```rust
#![feature(maybe_dangling)]
use std::mem::MaybeDangling;
const X: MaybeDangling<&bool> = unsafe { std::mem::transmute(&5u8) };
```
r? @WaffleLapkin
Avoid prematurely choosing a glob import
Fixes rust-lang/rust#153842
Use the following without introducing trait to explain:
```rust
mod a {
pub use crate::x::y as x; // single import #1
}
mod b {
pub mod x {
pub mod y {}
}
}
use a::x; // single import #2
use b::*; // glob import #3
fn main() {}
```
In current implementation, when `#1` is first resolved, `crate::x` is temporarily taken from glob import `#3` as `crate::b::x`. This happens because `single_import_can_define_name` will see that `#2` cannot define `x` (because it depends on `#1` and `#1` is ignored) and then return `false`. Later, during finalization, `crate::x` in `#1` resolves through single import `#2` instead, which no longer matches the initially cached module `crate::b::x` and triggers the ICE.
I think the resolver should keep this unresolved because `#2` may still define `x` to avoid prematurely choosing a glob import.
r? petrochenkov
Remove `ATTRIBUTE_ORDER`
r? @jdonszelmann
There's only a few attributes that use `KeepInnermost` and I think I like the consistency of just making them all `KeepOutermost`
Always check `ConstArgHasType` even when otherwise ignoring
fixes https://github.com/rust-lang/rust/issues/149774
helping @BoxyUwU finish up https://github.com/rust-lang/rust/pull/150322, this is a simple tweak/finishing-up of that PR.
this is a breaking change that crater detected has some issues with in Boxy's PR, and hence needs a t-types FCP. I can go and help fix those crates if/once the break is signed off on.
diagnostics: avoid ICE for undeclared generic parameter in impl
Avoid an ICE for:
struct A;
impl A<B> {}
The compiler no longer panics and can proceed to emit existing diagnostics.
Adds `tests/ui/missing/undeclared-generic-parameter.rs`.
Fixesrust-lang/rust#154165 and introduced by rust-lang/rust#152913
allow `incomplete_features` in most UI tests
This PR allows the `incomplete_features` lint for all UI tests except for the three directories with the largest number of tests (`traits`, `specialization` and `const-generics`) triggering this lint to keep the size of this PR manageable. The remaining three directories will be handled in followup PRs.
Part of https://github.com/rust-lang/rust/issues/154168.
ui/lto: move and rename two tests from issues/
Move:
- `tests/ui/issues/issue-44056.rs` -> `tests/ui/lto/lto-avx-target-feature.rs`
- The first test enables both AVX target features and LTO but does not exercise AVX-specific behavior. The test primarily checks that LTO builds successfully with these flags; place it under `ui/lto` for consistency.
- `tests/ui/issues/issue-51947.rs` -> `tests/ui/lto/lto-weak-merge-functions.rs`
- The second test exercises weak linkage interacting with LTO (merge-functions), so it should belong in `ui/lto`.
I have also added a commented line at the top of each test file indicating the issue it originated from.
Unknown -> Unsupported compression algorithm
Both zstd and zlib are *known* compression algorithms, they just may not be supported by the backend. We shouldn't mislead users into e.g. thinking they made a typo.
cc https://github.com/rust-lang/rust/issues/120953
Improve inline assembly error messages
by
- using `DiagSymbolList` to get nicely formatted lists
- mentioning the `modifier` when an invalid modifier is used. This is useful in case the span cannot be resolved (which I ran into).
diagnostics: avoid ICE in confusable_method_name for associated functions
Avoid unconditionally slicing `inputs()[1..]`, which assumes a `self` parameter. Use `is_method()` to conditionally skip the receiver, preventing out-of-bounds access and fixing suggestions for associated functions.
On E0277 tweak help when single type impls traits
When encountering an unmet predicate, when we point at the trait impls that do exist, if they are all for the same self type, tweak the wording to make it less verbose.
refactor RangeFromIter overflow-checks impl
Crates with different overflow-checks settings accessing the same RangeFromIter resulted in incorrect values being yielded
Fixesrust-lang/rust#154124
r? @tgross35
[BPF] add target feature allows-misaligned-mem-access
This PR adds the allows-misaligned-mem-access target feature to the BPF target. The feature can enable misaligned memory access support in the LLVM backend, aligning Rust’s BPF target behavior with the corresponding LLVM update introduced in [llvm/llvm-project#167013](https://github.com/llvm/llvm-project/pull/167013) (included in LLVM 22).
by
- using `DiagSymbolList` to get nicely formatted lists
- mentioning the `modifier` when an invalid modifier is used. This is useful in case the span cannot be resolved (which I ran into).
Avoid unconditionally slicing `inputs()[1..]`, which assumes a `self`
parameter. Use `is_method()` to conditionally skip the receiver,
preventing out-of-bounds access and fixing suggestions for associated
functions.
Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
Both zstd and zlib are *known* compression algorithms, they just may not
be supported by the backend. We shouldn't mislead users into e.g.
thinking they made a typo.
Avoid an ICE for:
struct A;
impl A<B> {}
The compiler no longer panics and can proceed to emit existing diagnostics.
Adds `tests/ui/missing/undeclared-generic-parameter.rs`.
Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
The test began passing in `nightly-2025-10-16`. Probably by c50aebba78
because it fixed two "does not live long enough" errors. The test fails
to compile with `nightly-2025-10-15` with such an error:
$ rustc +nightly-2025-10-15 --edition 2018 tests/ui/async-await/gat-is-send-across-await.rs
error: `impl G` does not live long enough
--> tests/ui/async-await/gat-is-send-across-await.rs:16:24
|
16 | let _: &dyn Send = &async move {
| ________________________^
17 | | let _gat = g.as_gat();
18 | | async{}.await
19 | | };
| |_____^
When encountering an unmet predicate, when we point at the trait impls that do exist, if they are all for the same self type, tweak the wording to make it less verbose.
Jacob Pratt