According to
https://discourse.llvm.org/t/rfc-volatile-access-to-non-dereferenceable-memory-may-be-well-defined/86303/4,
LLVM allows volatile operations on null and handles it correctly. This
should be allowed in Rust as well, because I/O memory may be hard-coded
to address 0 in some cases, like the AVR chip ATtiny1626.
A test case that ensured a failure when passing null to volatile was
removed, since it's now valid.
Due to the addition of `maybe_is_aligned` to `ub_checks`,
`maybe_is_aligned_and_not_null` was refactored to use it.
docs: revise restrictions on volatile operations
A distinction between usage on Rust memory vs. non-Rust memory was
introduced. Documentation was reworded to explain what that means, and
make explicit that:
- No trapping can occur from volatile operations;
- On Rust memory, all safety rules must be respected;
- On Rust memory, the primary difference from regular access is that
volatile always involves a memory dereference;
- On Rust memory, the only data affected by an operation is the one
pointed to in the argument(s) of the function;
- On Rust memory, provenance follows the same rules as non-volatile
access;
- On non-Rust memory, any address known to not contain Rust memory is
valid (including 0 and usize::MAX);
- On non-Rust memory, no Rust memory may be affected (it is implicit
that any other non-Rust memory may be affected, though, even if not
referenced by the pointer). This should be relevant when, for example,
reading register A causes a flag to change in register B, or writing
to A causes B to change in some way. Everything affected mustn't be
inside an allocation.
- On non-Rust memory, provenance is irrelevant and a pointer with none
can be used in a valid way.
fix: don't lint null as UB for volatile
Also remove a now-unneeded `allow` line.
fix: additional wording nits
Split-up stability_index query
This PR aims to move deprecation and stability processing away from the monolithic `stability_index` query, and directly implement `lookup_{deprecation,stability,body_stability,const_stability}` queries.
The basic idea is to:
- move per-attribute sanity checks into `check_attr.rs`;
- move attribute compatibility checks into the `MissingStabilityAnnotations` visitor;
- progressively dismantle the `Annotator` visitor and the `stability_index` query.
The first commit contains functional change, and now warns when `#[automatically_derived]` is applied on a non-trait impl block. The other commits should not change visible behaviour.
Perf in https://github.com/rust-lang/rust/pull/143845#issuecomment-3066308630 shows small but consistent improvement, except for unused-warnings case. That case being a stress test, I'm leaning towards accepting the regression.
This PR changes `check_attr`, so has a high conflict rate on that file. This should not cause issues for review.
Retire hir::*ItemRef.
This information was kept for various places that iterate on HIR to know about trait-items and impl-items.
This PR replaces them by uses of the `associated_items` query that contain pretty much the same information.
This shortens many spans to just `def_span`, which can be easier to read.
Check assoc consts and tys later like assoc fns
This PR
1. checks assoc consts and tys later like assoc fns
2. marks assoc consts appear in poly-trait-ref live
For assoc consts, considering
```rust
#![deny(dead_code)]
trait Tr { // ERROR trait `Tr` is never used
const I: Self;
}
struct Foo; //~ ERROR struct `Foo` is never constructed
impl Tr for Foo {
const I: Self = Foo;
}
fn main() {}
```
Current this will produce unused `I` instead of unused `Tr` and `Foo` ([play](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2024&gist=e0490d4a2d522cb70437b26e514a3d9c)), because `const I: Self = Foo;` will be added into the worklist at first:
```
error: associated constant `I` is never used
--> src/main.rs:4:11
|
3 | trait Tr { // ERROR trait `Tr` is never used
| -- associated constant in this trait
4 | const I: Self;
| ^
|
note: the lint level is defined here
--> src/main.rs:1:9
|
1 | #![deny(dead_code)]
| ^^^^^^^^^
error: could not compile `playground` (bin "playground") due to 1 previous error
```
This also happens to assoc tys, see the [new test](https://github.com/rust-lang/rust/compare/master...mu001999-contrib:rust:dead-code/impl-items?expand=1#diff-bf45fa403934a31c9d610a073ed2603d885e7e81572e8edf38b7f4e08a1f3531)
Fixesrust-lang/rust#126729
r? `````@petrochenkov`````
chore: Improve how the other suggestions message gets rendered
Note: This change is part of my ongoing work to use `annotate-snippets` as `rustc`'s emitter
This change started as a way to remove some specialty code paths from `annotate-snippets`, by making the "and {} other candidates" message get rendered like a secondary message with no level, but turned into a fix for the message's Unicode output. Before this change, when using the Unicode output, the other suggestions message would get rendered outside of the main suggestion block, making it feel disconnected from what it was referring to. This change makes it so that the message is on the last line of the block, aligning its rendering with other secondary messages, and making it clear what the message is referring to.
Before:
```
error[E0433]: failed to resolve: use of undeclared type `IntoIter`
╭▸ $DIR/issue-82956.rs:28:24
│
LL │ let mut iter = IntoIter::new(self);
│ ━━━━━━━━ use of undeclared type `IntoIter`
╰╴
help: consider importing one of these structs
╭╴
LL + use std::array::IntoIter;
├╴
LL + use std::collections::binary_heap::IntoIter;
├╴
LL + use std::collections::btree_map::IntoIter;
├╴
LL + use std::collections::btree_set::IntoIter;
╰╴
and 9 other candidates
```
After:
```
error[E0433]: failed to resolve: use of undeclared type `IntoIter`
╭▸ $DIR/issue-82956.rs:28:24
│
LL │ let mut iter = IntoIter::new(self);
│ ━━━━━━━━ use of undeclared type `IntoIter`
╰╴
help: consider importing one of these structs
╭╴
LL + use std::array::IntoIter;
├╴
LL + use std::collections::binary_heap::IntoIter;
├╴
LL + use std::collections::btree_map::IntoIter;
├╴
LL + use std::collections::btree_set::IntoIter;
│
╰ and 9 other candidates
```
Stop using `Key` trait unnecessarily
Few places where the `Key` trait was being used but not really for a useful reason. This fixes those usages.
Namely, `<Ty as Key>::default_span()` is `DUMMY_SP` anyways.
`tests/ui`: A New Order [16/N]
> [!NOTE]
>
> Intermediate commits are intended to help review, but will be squashed prior to merge.
Some `tests/ui/` housekeeping, to trim down number of tests directly under `tests/ui/`. Part of rust-lang/rust#133895.
r? `@tgross35`
(just small one to test new method, also I should squash all this commits except move commit, so we after review will end up having like one move commit and one commit with changes, right?)
Fix suggestion spans inside macros for the `unused_must_use` lint
This PR fixes the suggestion spans inside macros for the `unused_must_use` lint by trying to find the oldest ancestor span.
Fixes https://github.com/rust-lang/rust/issues/143025
Port `#[track_caller]` to the new attribute system
r? ``@oli-obk``
depends on https://github.com/rust-lang/rust/pull/142493Closesrust-lang/rust#142783
(didn't add a test for this, this situation should simply never come up again, the code was simply wrong. lmk if I should add it, but it won't test something very useful)
Also emit suggestions for usages in the `non_upper_case_globals` lint
This PR adds suggestions for all the usages of the renamed item in the warning of the `non_upper_case_globals` lint.
Fixes https://github.com/rust-lang/rust/issues/124061
Marks ADT live if it appears in pattern
Marks ADT live if it appears in pattern, it implies the construction of the ADT.
1. Then we can detect unused private ADTs impl `Default`, without special logics for `Default` and other std traits.
2. We can also remove `rustc_trivial_field_reads` on `Default`, and the logic in `should_ignore_item` (introduced by rust-lang/rust#126302).
Fixesrust-lang/rust#120770
Extracted from rust-lang/rust#128637.
r? `@petrochenkov`
Rewrite `inline` attribute parser to use new infrastructure and improve diagnostics for all parsed attributes
r? `@oli-obk`
This PR:
- creates a new parser for inline attributes
- creates consistent error messages and error codes between attribute parsers; inline and others
- as such changes a few error messages for other attributes to be (in my eyes) much more consistent
- tests ast-lowering lints introduced by rust-lang/rust#138164 since this is now useful for the first time
- Coalesce some useless error codes
Builds on top of rust-lang/rust#138164Closesrust-lang/rust#137950
