raw_eq: using it on bytes with provenance is not UB (outside const-eval)
The current behavior of raw_eq violates provenance monotonicity. See https://github.com/rust-lang/rust/pull/124921 for an explanation of provenance monotonicity. It is violated in raw_eq because comparing bytes without provenance is well-defined, but adding provenance makes the operation UB.
So remove the no-provenance requirement from raw_eq. However, the requirement stays in-place for compile-time invocations of raw_eq, that indeed cannot deal with provenance.
Cc `@rust-lang/opsem`
Better handle suggestions for the already present code and fix some suggestions
When a suggestion part is for code that is already present, skip it. If all the suggestion parts for a suggestion are for code that is already there, do not emit the suggestion.
Fix two suggestions that treat `span_suggestion` as if it were `span_help`.
```
error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
--> $DIR/E0283.rs:30:21
|
LL | fn create() -> u32;
| ------------------- `Coroutine::create` defined here
...
LL | let cont: u32 = Coroutine::create();
| ^^^^^^^^^^^^^^^^^^^ cannot call associated function of trait
|
help: use a fully-qualified path to a specific available implementation
|
LL | let cont: u32 = <Impl as Coroutine>::create();
| ++++++++ +
LL | let cont: u32 = <AnotherImpl as Coroutine>::create();
| +++++++++++++++ +
```
When a suggestion part is for already present code, do not highlight it. If after that there are no highlights left, do not show the suggestion at all.
Fix clippy lint suggestion incorrectly treated as `span_help`.
interpret: on a signed deref check, mention the right pointer in the error
When a negative offset (like `ptr.offset(-10)`) goes out-of-bounds, we currently show an error saying that we expect the *resulting* pointer to be inbounds for 10 bytes. That's confusing, so this PR makes it so that instead we say that we expect the *original* pointer `ptr` to have 10 bytes *to the left*.
I also realized I can simplify the pointer arithmetic logic and handling of "staying inbounds of a target `usize`" quite a bit; the second commit does that.
More unsafe attr verification
This code denies unsafe on attributes such as `#[test]` and `#[ignore]`, while also changing the `MetaItem` parsing so `unsafe` in args like `#[allow(unsafe(dead_code))]` is not accidentally allowed.
Tracking:
- https://github.com/rust-lang/rust/issues/123757
Emit an error if `#[optimize]` is applied to an incompatible item
#54882
The RFC specifies that this should emit a lint. I used the same allow logic as the `coverage` attribute (also allowing modules and impl blocks) - this should possibly be changed depending on if it's decided to allow 'propogation' of the attribute.
Rollup of 7 pull requests
Successful merges:
- #123813 (Add `REDUNDANT_IMPORTS` lint for new redundant import detection)
- #126697 ([RFC] mbe: consider the `_` in 2024 an expression)
- #127159 (match lowering: Hide `Candidate` from outside the lowering algorithm)
- #128244 (Peel off explicit (or implicit) deref before suggesting clone on move error in borrowck, remove some hacks)
- #128431 (Add myself as VxWorks target maintainer for reference)
- #128438 (Add special-case for [T, 0] in dropck_outlives)
- #128457 (Fix docs for OnceLock::get_mut_or_init)
r? `@ghost`
`@rustbot` modify labels: rollup
derive(SmartPointer): require pointee to be maybe sized
cc ``@Darksonn``
So `#[pointee]` has to be `?Sized` in order for deriving `SmartPointer` to be meaningful.
cc ``@compiler-errors`` for suggestions in #127681
Properly mark loop as diverging if it has no breaks
Due to specifics about the desugaring of the `.await` operator, HIR typeck doesn't recognize that `.await`ing an `impl Future<Output = !>` will diverge in the same way as calling a `fn() -> !`.
This is because the await operator desugars to approximately:
```rust
loop {
match future.poll(...) {
Poll::Ready(x) => break x,
Poll::Pending => {}
}
}
```
We know that the value of `x` is `!`, however since `break` is a coercion site, we coerce `!` to some `?0` (the type of the loop expression). Then since the type of the `loop {...}` expression is `?0`, we will not detect the loop as diverging like we do with other expressions that evaluate to `!`:
0b5eb7ba7b/compiler/rustc_hir_typeck/src/expr.rs (L240-L243)
We can technically fix this in two ways:
1. Make coercion of loop exprs more eagerly result in a type of `!` when the only break expressions have type `!`.
2. Make loops understand that all of that if they have only diverging break values, then the loop diverges as well.
(1.) likely has negative effects on inference, and seems like a weird special case to drill into coercion. However, it turns out that (2.) is very easy to implement, we already record whether a loop has any break expressions, and when we do so, we actually skip over any break expressions with diverging values!:
0b5eb7ba7b/compiler/rustc_hir_typeck/src/expr.rs (L713-L716)
Thus, we can consider the loop as diverging if we see that it has no breaks, which is the change implemented in this PR.
This is not usually a problem in regular code for two reasons:
1. In regular code, we already mark `break diverging()` as unreachable if `diverging()` is unreachable. We don't do this for `.await`, since we suppress unreachable errors within `.await` (#64930). Un-suppressing this code will result in spurious unreachable expression errors pointing to internal await machinery.
3. In loops that truly have no breaks (e.g. `loop {}`), we already evaluate the type of the loop to `!`, so this special case is kinda moot. This only affects loops that have `break`s with values of type `!`.
Thus, this seems like a change that may affect more code than just `.await`, but it likely does not in meaningful ways; if it does, it's certainly correct to apply.
Fixes#128434
Peel off explicit (or implicit) deref before suggesting clone on move error in borrowck, remove some hacks
Also remove a heck of a lot of weird hacks in `suggest_cloning` that I don't think we should have around.
I know this regresses tests, but I don't believe most of these suggestions were accurate, b/c:
1. They either produced type errors (e.g. turning `&x` into `x.clone()`)
2. They don't fix the issue
3. They fix the issue ostensibly, but introduce logic errors (e.g. cloning a `&mut Option<T>` to then `Option::take` out...)
Most of the suggestions are still wrong, but they're not particularly *less* wrong IMO.
Stacked on top of #128241, which is an "obviously worth landing" subset of this PR.
r? estebank
match lowering: Hide `Candidate` from outside the lowering algorithm
The internals of `Candidate` are tricky and a source of confusion. This PR makes it so we don't expose `Candidate`s outside the lowering algorithm. Now:
- false edges are handled in `lower_match_tree`;
- `lower_match_tree` takes a list of patterns as input;
- `lower_match_tree` returns a flat datastructure that contains only the necessary information.
r? ```@matthewjasper```
Add `REDUNDANT_IMPORTS` lint for new redundant import detection
Defaults to Allow for now. Stacked on #123744 to avoid merge conflict, but much easier to review all as one.
r? petrochenkov
Rollup of 9 pull requests
Successful merges:
- #126454 (bump-stage0: use IndexMap for determinism)
- #127681 (derive(SmartPointer): rewrite bounds in where and generic bounds)
- #127830 (When an archive fails to build, print the path)
- #128151 (Structured suggestion for `extern crate foo` when `foo` isn't resolved in import)
- #128387 (More detailed note to deprecate ONCE_INIT)
- #128388 (Match LLVM ABI in `extern "C"` functions for `f128` on Windows)
- #128402 (Attribute checking simplifications)
- #128412 (Remove `crate_level_only` from `ELIDED_LIFETIMES_IN_PATHS`)
- #128430 (Use a separate pattern type for `rustc_pattern_analysis` diagnostics )
r? `@ghost`
`@rustbot` modify labels: rollup
Remove `crate_level_only` from `ELIDED_LIFETIMES_IN_PATHS`
As far as I can tell, we provide the right node id to the `ELIDED_LIFETIMES_IN_PATHS` lint:
f8060d282d/compiler/rustc_resolve/src/late.rs (L2015-L2027)
So I've gone ahead and removed the restriction from this lint.
Structured suggestion for `extern crate foo` when `foo` isn't resolved in import
When encountering a name in an import that could have come from a crate that wasn't imported, use a structured suggestion to suggest `extern crate foo;` pointing at the right place in the crate.
When encountering `_` in an import, do not suggest `extern crate _;`.
```
error[E0432]: unresolved import `spam`
--> $DIR/import-from-missing-star-3.rs:2:9
|
LL | use spam::*;
| ^^^^ maybe a missing crate `spam`?
|
help: consider importing the `spam` crate
|
LL + extern crate spam;
|
```
derive(SmartPointer): rewrite bounds in where and generic bounds
Fix#127647
Due to the `Unsize` bounds, we need to commute the bounds on the pointee type to the new self type.
cc ```@Darksonn```
Update to LLVM 19
The LLVM 19.1.0 final release is planned for Sep 3rd. The rustc 1.82 stable release will be on Oct 17th.
The unstable MC/DC coverage support is temporarily broken by this update. It will be restored by https://github.com/rust-lang/rust/pull/126733. The implementation changed substantially in LLVM 19, and there are no plans to support both the LLVM 18 and LLVM 19 implementation at the same time.
Compatibility note for wasm:
> WebAssembly target support for the `multivalue` target feature has changed when upgrading to LLVM 19. Support for generating functions with multiple returns no longer works and `-Ctarget-feature=+multivalue` has a different meaning than it did in LLVM 18 and prior. The WebAssembly target features `multivalue` and `reference-types` are now both enabled by default, but generated code is not affected by default. These features being enabled are encoded in the `target_features` custom section and may affect downstream tooling such as `wasm-opt` consuming the module, but the actual generated WebAssembly will continue to not use either `multivalue` or `reference-types` by default. There is no longer any supported means to generate a module that has a function with multiple returns.
Related changes:
* https://github.com/rust-lang/rust/pull/127605
* https://github.com/rust-lang/rust/pull/127613
* https://github.com/rust-lang/rust/pull/127654
* https://github.com/rust-lang/rust/pull/128141
* https://github.com/llvm/llvm-project/pull/98933
Fixes https://github.com/rust-lang/rust/issues/121444.
Fixes https://github.com/rust-lang/rust/issues/128212.
This makes it possible for the `unsafe(...)` syntax to only be
valid at the top level, and the `NestedMetaItem`s will automatically
reject `unsafe(...)`.
Mark `Parser::eat`/`check` methods as `#[must_use]`
These methods return a `bool`, but we probably should either use these values or explicitly throw them away (e.g. when we just want to unconditionally eat a token if it exists).
I changed a few places from `eat` to `expect`, but otherwise I tried to leave a comment explaining why the `eat` was okay.
This also adds a test for the `pattern_type!` macro, which used to silently accept a missing `is` token.
Detect non-lifetime binder params shadowing item params
We should check that `for<T>` shadows `T` from an item in the same way that `for<'a>` shadows `'a` from an item.
r? ``@petrochenkov`` since you're familiar w the nuances of rib kinds
