No prejudice against re-enabling them if the nominations include a bit
more context on _why_ it's automatically nominated and _which_
regression(s) are being addressed. Or as proposed, it could also simply
become a reminder-to-nominate _comment_.
Update books
## rust-lang/book
1 commits in 33f1af40cc44dde7e3e892f7a508e6f427d2cbc6..1d7c3e6abec2d5a9bfac798b29b7855b95025426
2025-09-28 21:24:16 UTC to 2025-09-28 21:24:16 UTC
- Chunk of chapters from copyedit (rust-lang/book#4506)
## rust-lang/edition-guide
1 commits in aa6ce337c0adf7a63e33960d184270f2a45ab9ef..e2ed891f00361efc26616d82590b1c85d7a8920e
2025-10-01 17:11:54 UTC to 2025-10-01 17:11:54 UTC
- link to never type fallback lint as deny by default (rust-lang/edition-guide#377)
## rust-lang/nomicon
1 commits in f17a018b9989430967d1c58e9a12c51169abc744..23fc2682f8fcb887f77d0eaabba708809f834c11
2025-09-24 10:10:31 UTC to 2025-09-24 10:10:31 UTC
- a typo in ffi.md (rust-lang/nomicon#502)
## rust-lang/reference
13 commits in cc7247d8dfaef4c39000bb12c55c32ba5b5ba976..e11adf6016a362766eea5a3f9832e193994dd0c8
2025-09-29 00:55:42 UTC to 2025-09-23 23:33:32 UTC
- const functions: separate rule about users and rule about what is allowed in such functions (rust-lang/reference#2013)
- use "tuple enum variant" more consistently (rust-lang/reference#2015)
- Remove caveats related to `format_args!` expansion (rust-lang/reference#2017)
- RISC-V: Extension Updates (including document references) (rust-lang/reference#2002)
- Move inferred sentence to an example block (rust-lang/reference#2019)
- Add triagebot range-diff feature (rust-lang/reference#2011)
- use AND when searching for multiple terms (rust-lang/reference#2016)
- enumerations.md: fix pluralisation (rust-lang/reference#2014)
- const_eval.md: use sentence case for section title, for consistency (rust-lang/reference#2012)
- destructors.md: improve readability by adding pauses (rust-lang/reference#2007)
- RISC-V: Add vector state registers (rust-lang/reference#2005)
- destructors.md: point to core:: instead of std:: (rust-lang/reference#2006)
- Create Whitespace grammar productions (rust-lang/reference#1991)
Initialize llvm submodule if not already the case to run citool
While working on https://github.com/rust-lang/rust/pull/146414, I ran the following command (to run CI docker locally):
```
cargo run --manifest-path src/ci/citool/Cargo.toml run-local --type pr x86_64-gnu-gcc
```
However, since I didn't have `src/llvm` submodule initialized, it failed. Apparently it's a common issue for people using this tool so this PR removes this small inconvenience.
r? ``@Kobzol``
implement `Box::take`
Tracking issue: https://github.com/rust-lang/rust/issues/147212
I'm not entirely sure about the wording of the doc comment, if anyone has any suggestions that'd be great :)
Don't enable shared memory by default with Wasm atomics
This prepares us for a future where LLVM eventually stabilizes the atomics target feature, in which case we don't want to inflate atomics with threads. Otherwise users would be stuck with shared memory even when they don't want it/need it.
### Context
Currently the atomics target features is unstable and can't be used without re-building Std with it (`-Zbuild-std`).
Enabling the atomics target feature automatically enables shared memory.
Shared memory is required to actually allow multi-threading.
However, shared memory comes with a performance overhead when atomic instructions aren't able to be lowered to regular memory access instructions or when interacting with certain Web APIs.
So it is very undesirable to enable shared memory by default for the majority of users.
While it is possible to use atomics without shared memory, the question remains what use-case this scenario has.
The only one I can think of would involve multiple memories, where the main memory remains un-shared but a second shared memory exists. While Rust doesn't support multiple memories, it might be possible with inline assembly (rust-lang/rust#136382).
So alternatively, we might consider *not* enabling atomics by default even when LLVM does. In which case everything would remain the same.
---
This will break current Web multi-threading users. To address this they can add the following `RUSTFLAGS`:
```
-Clink-args=--shared-memory,--max-memory=1073741824,--import-memory,--export=__wasm_init_tls,--export=__tls_size,--export=__tls_align,--export=__tls_base
```
We could add a new experimental flag that enables the right linker arguments for users, but I feel that's not in Rusts scope. Or like suggested before: a Rust-only `threads` target feature.
Addresses rust-lang/rust#77839.
r? ``@alexcrichton``
Forbid `//@ compile-flags: -Cincremental=` in tests
Tests should not try to manually enable incremental compilation with `-Cincremental`, because that typically results in stray directories being created in the repository root.
Also, if the incremental directory is not cleared, there is a risk of interference between successive runs of the same test.
Instead, use the `//@ incremental` directive, which instructs compiletest to handle the details of passing `-Cincremental` with a fresh directory.
Tweak handling of "struct like start" where a struct isn't supported
This improves the case where someone tries to write a `match` expr where the patterns have type ascription syntax. Makes them less verbose, by giving up on the first encounter in the block, and makes them more accurate by only treating them as a struct literal if successfully parsed as such.
Before, encountering something like `match a { b:` would confuse the parser and think everything after `match` *must* be a struct, and if it wasn't it would generate a cascade of unnecessary diagnostics.
mbe: Implement `unsafe` attribute rules
This implements `unsafe attr` rules for declarative `macro_rules!` attributes, as specified in [RFC 3697](https://github.com/rust-lang/rfcs/pull/3697).
An invocation of an attribute that uses an `unsafe attr` rule requires the `unsafe(attr(...))` syntax.
An invocation of an attribute that uses an ordinary `attr` rule must *not* use the `unsafe(attr(...))` syntax.
`unsafe` is only supported on an `attr` rule, not any other kind of `macro_rules!` rule.
Tracking issue for `macro_rules!` attributes: https://github.com/rust-lang/rust/issues/143547
Support `#[rustc_align_static]` inside `thread_local!`
Tracking issue: rust-lang/rust#146177
```rust
thread_local! {
#[rustc_align_static(64)]
static SO_ALIGNED: u64 = const { 0 };
}
```
This increases the amount of recursion the macro performs (once per attribute in addition to the previous once per item), making it easier to hit the recursion limit. I’ve added workarounds to limit the impact in the case of long doc comments, but this still needs a crater run just in case.
r? libs
``@rustbot`` label A-attributes A-macros A-thread-locals F-static_align T-libs
Turn ProjectionElem::Subtype into CastKind::Subtype
I noticed that drop elaboration can't, in general, handle `ProjectionElem::SubType`. It creates a disjoint move path that overlaps with other move paths. (`Subslice` does too, and I'm working on a different PR to make that special case less fragile.) If its skipped and treated as the same move path as its parent then `MovePath.place` has multiple possible projections. (It would probably make sense to remove all `Subtype` projections for the canonical place but it doesn't make sense to have this special case for a problem that doesn't actually occur in real MIR.)
The only reason this doesn't break is that `Subtype` is always the sole projection of the local its applied to. For the same reason, it works fine as a `CastKind` so I figured that makes more sense than documenting and validating this hidden invariant.
cc rust-lang/rust#112651, rust-lang/rust#133258
r? Icnr (bc you've been the main person dealing with `Subtype` it looks like)
Turn ProjectionElem::Subtype into CastKind::Subtype
I noticed that drop elaboration can't, in general, handle `ProjectionElem::SubType`. It creates a disjoint move path that overlaps with other move paths. (`Subslice` does too, and I'm working on a different PR to make that special case less fragile.) If its skipped and treated as the same move path as its parent then `MovePath.place` has multiple possible projections. (It would probably make sense to remove all `Subtype` projections for the canonical place but it doesn't make sense to have this special case for a problem that doesn't actually occur in real MIR.)
The only reason this doesn't break is that `Subtype` is always the sole projection of the local its applied to. For the same reason, it works fine as a `CastKind` so I figured that makes more sense than documenting and validating this hidden invariant.
cc rust-lang/rust#112651, rust-lang/rust#133258
r? Icnr (bc you've been the main person dealing with `Subtype` it looks like)
Tests should not try to manually enable incremental compilation with
`-Cincremental`, because that typically results in stray directories being
created in the repository root.
Instead, use the `//@ incremental` directive, which instructs compiletest to
handle the details of passing `-Cincremental` with a fresh directory.
It's possible for targets to only support `core` and not `alloc`.
Instead of building alloc unconditionally, pass a list of crates to
build into `std_cargo`, and only pass `-p alloc` if the list of crates
wasn't already filtered to a subset.
The original use case was to reuse `std_cargo` for a rustc_driver that
doesn't emit metadata. But this seems like a reasonable change
regardless.
`LegacyAttr` is only used for builtin attributes, and builtin attributes
have their safety checked by `check_attribute_safety`, so we don't need
to check `unsafety` here.
