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
Update cargo
6 commits in fc1518ef02b77327d70d4026b95ea719dd9b8c51..2251525ae503fa196f6d7f9ce6d32eccb2d5f044
2025-06-06 04:49:44 +0000 to 2025-06-16 22:01:27 +0000
- feat: Add custom completer for `cargo remove <TAB>` (rust-lang/cargo#15662)
- chore(deps): update msrv (3 versions) to v1.85 (rust-lang/cargo#15668)
- refactor: replace InternedString with Cow in IndexPackage (rust-lang/cargo#15559)
- highlight the correct words (rust-lang/cargo#15659)
- CHANGELOG.md: typo (rust-lang/cargo#15660)
- Use `Not::not` rather than a custom `is_false` function (rust-lang/cargo#15645)
Sized Hierarchy: Part I
This patch implements the non-const parts of rust-lang/rfcs#3729. It introduces two new traits to the standard library, `MetaSized` and `PointeeSized`. See the RFC for the rationale behind these traits and to discuss whether this change makes sense in the abstract.
These traits are unstable (as is their constness), so users cannot refer to them without opting-in to `feature(sized_hierarchy)`. These traits are not behind `cfg`s as this would make implementation unfeasible, there would simply be too many `cfg`s required to add the necessary bounds everywhere. So, like `Sized`, these traits are automatically implemented by the compiler.
RFC 3729 describes changes which are necessary to preserve backwards compatibility given the introduction of these traits, which are implemented and as follows:
- `?Sized` is rewritten as `MetaSized`
- `MetaSized` is added as a default supertrait for all traits w/out an explicit sizedness supertrait already.
There are no edition migrations implemented in this, as these are primarily required for the constness parts of the RFC and prior to stabilisation of this (and so will come in follow-up PRs alongside the const parts). All diagnostic output should remain the same (showing `?Sized` even if the compiler sees `MetaSized`) unless the `sized_hierarchy` feature is enabled.
Due to the use of unstable extern types in the standard library and rustc, some bounds in both projects have had to be relaxed already - this is unfortunate but unavoidable so that these extern types can continue to be used where they were before. Performing these relaxations in the standard library and rustc are desirable longer-term anyway, but some bounds are not as relaxed as they ideally would be due to the inability to relax `Deref::Target` (this will be investigated separately).
It is hoped that this is implemented such that it could be merged and these traits could exist "under the hood" without that being observable to the user (other than in any performance impact this has on the compiler, etc). Some details might leak through due to the standard library relaxations, but this has not been observed in test output.
**Notes:**
- Any commits starting with "upstream:" can be ignored, as these correspond to other upstream PRs that this is based on which have yet to be merged.
- This best reviewed commit-by-commit. I've attempted to make the implementation easy to follow and keep similar changes and test output updates together.
- Each commit has a short description describing its purpose.
- This patch is large but it's primarily in the test suite.
- I've worked on the performance of this patch and a few optimisations are implemented so that the performance impact is neutral-to-minor.
- `PointeeSized` is a different name from the RFC just to make it more obvious that it is different from `std::ptr::Pointee` but all the names are yet to be bikeshed anyway.
- `@nikomatsakis` has confirmed [that this can proceed as an experiment from the t-lang side](https://rust-lang.zulipchat.com/#narrow/channel/435869-project-goals/topic/SVE.20and.20SME.20on.20AArch64.20.28goals.23270.29/near/506196491)
- FCP in https://github.com/rust-lang/rust/pull/137944#issuecomment-2912207485Fixesrust-lang/rust#79409.
r? `@ghost` (I'll discuss this with relevant teams to find a reviewer)
It isn't clear why the `Deref` impl isn't found for this in a stage two
build, but presumably relates to `rustc_middle::ty::RawList` containing
an extern type and `Deref` not yet being relaxed to `PointeeSized` (this
is technically a breaking change but unlikely to be one and will be
tested in a follow-up).
clarify `rustc_do_not_const_check` comment
~~Given that we have used this attribute for other reasons before it seems appropriate to make this a "usually".~~
Add function name as a pointer
cc ```@rust-lang/wg-const-eval```
Reduce precedence of expressions that have an outer attr
Previously, `-Zunpretty=expanded` would expand this program as follows:
```rust
#![feature(stmt_expr_attributes)]
macro_rules! repro {
($e:expr) => {
#[allow(deprecated)] $e
};
}
#[derive(Default)]
struct Thing {
#[deprecated]
field: i32,
}
fn main() {
let thing = Thing::default();
let _ = repro!(thing).field;
}
```
```rs
#![feature(prelude_import)]
#![feature(stmt_expr_attributes)]
#[prelude_import]
use std::prelude::rust_2021::*;
#[macro_use]
extern crate std;
struct Thing {
#[deprecated]
field: i32,
}
#[automatically_derived]
impl ::core::default::Default for Thing {
#[inline]
fn default() -> Thing {
Thing { field: ::core::default::Default::default() }
}
}
fn main() {
let thing = Thing::default();
let _ = #[allow(deprecated)] thing.field;
}
```
This is not the correct expansion. The correct output would have `(#[allow(deprecated)] thing).field` with the attribute applying only to `thing`, not to `thing.field`.
Unimplement unsized_locals
Implements https://github.com/rust-lang/compiler-team/issues/630
Tracking issue here: https://github.com/rust-lang/rust/issues/111942
Note that this just removes the feature, not the implementation, and does not touch `unsized_fn_params`. This is because it is required to support `Box<dyn FnOnce()>: FnOnce()`.
There may be more that should be removed (possibly in follow up prs)
- the `forget_unsized` function and `forget` intrinsic.
- the `unsized_locals` test directory; I've just fixed up the tests for now
- various codegen support for unsized values and allocas
cc ``@JakobDegen`` ``@oli-obk`` ``@Noratrieb`` ``@programmerjake`` ``@bjorn3``
``@rustbot`` label F-unsized_locals
Fixesrust-lang/rust#79409
Temporary lifetime extension through tuple struct and tuple variant constructors
This makes temporary lifetime extension work for tuple struct and tuple variant constructors, such as `Some()`.
Before:
```rust
let a = &temp(); // Extended
let a = Some(&temp()); // Not extended :(
let a = Some { 0: &temp() }; // Extended
```
After:
```rust
let a = &temp(); // Extended
let a = Some(&temp()); // Extended
let a = Some { 0: &temp() }; // Extended
```
So, with this change, this works:
```rust
let a = Some(&String::from("hello")); // New: String lifetime now extended!
println!("{a:?}");
```
Until now, we did not extend through tuple struct/variant constructors (like `Some`), because they are function calls syntactically, and we do not want to extend the String lifetime in:
```rust
let a = some_function(&String::from("hello")); // String not extended!
```
However, it turns out to be very easy to distinguish between regular functions and constructors at the point where we do lifetime extension.
In practice, constructors nearly always use UpperCamelCase while regular functions use lower_snake_case, so it should still be easy to for a human programmer at the call site to see whether something qualifies for lifetime extension or not.
This needs a lang fcp.
---
More examples of what will work after this change:
```rust
let x = Person {
name: "Ferris",
job: Some(&Job { // `Job` now extended!
title: "Chief Rustacean",
organisation: "Acme Ltd.",
}),
};
dbg!(x);
```
```rust
let file = if use_stdout {
None
} else {
Some(&File::create("asdf")?) // `File` now extended!
};
set_logger(file);
```
```rust
use std::path::Component;
let c = Component::Normal(&OsString::from(format!("test-{num}"))); // OsString now extended!
assert_eq!(path.components.first().unwrap(), c);
```
