Commit Graph

8366 Commits

Author SHA1 Message Date
Michael Goulet
ecd2d11573 Remove redundant flags that can be inferred from the HIR 2024-08-25 16:21:00 -04:00
bors
a60a9e567a Auto merge of #129464 - GuillaumeGomez:rollup-ckfqd7h, r=GuillaumeGomez
Rollup of 9 pull requests

Successful merges:

 - #128511 (Document WebAssembly target feature expectations)
 - #129243 (do not build `cargo-miri` by default on stable channel)
 - #129263 (Add a missing compatibility note in the 1.80.0 release notes)
 - #129276 (Stabilize feature `char_indices_offset`)
 - #129350 (adapt integer comparison tests for LLVM 20 IR changes)
 - #129408 (Fix handling of macro arguments within the `dropping_copy_types` lint)
 - #129426 (rustdoc-search: use tighter json for names and parents)
 - #129437 (Fix typo in a help diagnostic)
 - #129457 (kobzol vacation)

r? `@ghost`
`@rustbot` modify labels: rollup
2024-08-23 10:56:34 +00:00
Guillaume Gomez
81aca633bb
Rollup merge of #129408 - Urgau:macro-arg-drop_copy, r=compiler-errors
Fix handling of macro arguments within the `dropping_copy_types` lint

This PR fixes the handling of spans with different context (aka macro arguments) than the primary expression within the different `{drop,forget}ing_copy_types` and `{drop,forget}ing_references` lints.

<details>
<summary>Before</summary>

```
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
 --> drop_writeln.rs:5:5
  |
5 |     drop(writeln!(&mut msg, "test"));
  |     ^^^^^--------------------------^
  |          |
  |          argument has type `Result<(), std::fmt::Error>`
  |
  = note: `#[warn(dropping_copy_types)]` on by default
help: use `let _ = ...` to ignore the expression or result
 --> /home/[..]/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/macros/mod.rs:688:9
  |
68|         let _ =
  |         ~~~~~~~
```

</details>

<details>
<summary>With this PR</summary>

```
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
 --> drop_writeln.rs:5:5
  |
5 |     drop(writeln!(&mut msg, "test"));
  |     ^^^^^--------------------------^
  |          |
  |          argument has type `Result<(), std::fmt::Error>`
  |
  = note: `#[warn(dropping_copy_types)]` on by default
help: use `let _ = ...` to ignore the expression or result
  |
5 -     drop(writeln!(&mut msg, "test"));
5 +     let _ = writeln!(&mut msg, "test");
  |
```

</details>

``````@rustbot`````` label +L-dropping_copy_types
2024-08-23 12:32:16 +02:00
Michael Goulet
8eb15586c6 Don't trigger refinement lint if predicates reference errors 2024-08-22 12:34:12 -04:00
Urgau
6a878a9630 Fix handling of macro arguments within the `dropping_copy_types lint 2024-08-22 13:32:01 +02:00
bors
8269be147b Auto merge of #129398 - matthiaskrgr:rollup-50l01ry, r=matthiaskrgr
Rollup of 8 pull requests

Successful merges:

 - #128432 (WASI: forbid `unsafe_op_in_unsafe_fn` for `std::{os, sys}`)
 - #129373 (Add missing module flags for CFI and KCFI sanitizers)
 - #129374 (Use `assert_unsafe_precondition!` in `AsciiChar::digit_unchecked`)
 - #129376 (Change `assert_unsafe_precondition` docs to refer to `check_language_ub`)
 - #129382 (Add `const_cell_into_inner` to `OnceCell`)
 - #129387 (Advise against removing the remaining Python scripts from `tests/run-make`)
 - #129388 (Do not rely on names to find lifetimes.)
 - #129395 (Pretty-print own args of existential projections (dyn-Trait w/ GAT constraints))

r? `@ghost`
`@rustbot` modify labels: rollup
2024-08-22 08:20:49 +00:00
Matthias Krüger
9d39b59862
Rollup merge of #129395 - fmease:pp-dyn-w-gat, r=compiler-errors
Pretty-print own args of existential projections (dyn-Trait w/ GAT constraints)

Previously we would just drop them. This bug isn't that significant as it can only be triggered by user code that constrains GATs inside trait object types which is currently gated under the interim feature `generic_associated_types_extended` (whose future is questionable) or on stable if the GATs are 'disabled' in dyn-Trait via `where Self: Sized` (in which case the assoc type bindings get ignored anyway (and trigger the warn-by-default lint `unused_associated_type_bounds`)), so yeah.

Affects diagnostic output and output of `std::any::type_name{_of_val}`.
2024-08-22 08:17:23 +02:00
bors
739b1fdb15 Auto merge of #129365 - matthiaskrgr:rollup-ebwx6ya, r=matthiaskrgr
Rollup of 9 pull requests

Successful merges:

 - #127279 (use old ctx if has same expand environment during decode span)
 - #127945 (Implement `debug_more_non_exhaustive`)
 - #128941 ( Improve diagnostic-related lints: `untranslatable_diagnostic` & `diagnostic_outside_of_impl`)
 - #129070 (Point at explicit `'static` obligations on a trait)
 - #129187 (bootstrap: fix clean's remove_dir_all implementation)
 - #129231 (improve submodule updates)
 - #129264 (Update `library/Cargo.toml` in weekly job)
 - #129284 (rustdoc: animate the `:target` highlight)
 - #129302 (compiletest: use `std::fs::remove_dir_all` now that it is available)

r? `@ghost`
`@rustbot` modify labels: rollup
2024-08-22 05:17:27 +00:00
León Orell Valerian Liehr
080c2ca2dc
Pretty-print own args of existential projections 2024-08-22 06:22:36 +02:00
Camille GILLOT
ca7c55f050 Do not rely on names to find lifetimes. 2024-08-22 02:20:05 +00:00
Matthias Krüger
00e109f3d4
Rollup merge of #129364 - jswrenn:transmute-layout-errs, r=compiler-errors
safe transmute: gracefully bubble-up layout errors

Changes `.unwrap()`s to `?` to avoid ICEs. Adds ui tests.

Fixes #129327

Tracking Issue: https://github.com/rust-lang/rust/issues/99571

r​? `@compiler-errors`
2024-08-21 21:58:29 +02:00
Matthias Krüger
5a93c74a02
Rollup merge of #128727 - RalfJung:conflicting-repr-future-incompat, r=lcnr
bump conflicting_repr_hints lint to be shown in dependencies

This has been a future compatibility lint for years, let's bump it up to be shown in dependencies (so that hopefully we can then make it a hard error fairly soon).

Cc https://github.com/rust-lang/rust/issues/68585
2024-08-21 21:58:27 +02:00
Jack Wrenn
e2328ebd7f safe transmute: gracefully bubble-up layout errors
Changes `.unwrap()`s to `?` to avoid ICEs. Adds ui tests.

Fixes #129327
2024-08-21 18:06:02 +00:00
Matthias Krüger
ffdbd9d6c8
Rollup merge of #129070 - estebank:static-trait, r=davidtwco
Point at explicit `'static` obligations on a trait

Given `trait Any: 'static` and a `struct` with a `Box<dyn Any + 'a>` field, point at the `'static` bound in `Any` to explain why `'a: 'static`.

```
error[E0478]: lifetime bound not satisfied
   --> f202.rs:2:12
    |
2   |     value: Box<dyn std::any::Any + 'a>,
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: lifetime parameter instantiated with the lifetime `'a` as defined here
   --> f202.rs:1:14
    |
1   | struct Hello<'a> {
    |              ^^
note: but lifetime parameter must outlive the static lifetime
   --> /home/gh-estebank/rust/library/core/src/any.rs:113:16
    |
113 | pub trait Any: 'static {
    |                ^^^^^^^
```

Partially address #33652.
2024-08-21 19:35:12 +02:00
Esteban Küber
f5bae722be Point at explicit 'static obligations on a trait
Given `trait Any: 'static` and a `struct` with a `Box<dyn Any + 'a>` field, point at the `'static` bound in `Any` to explain why `'a: 'static`.

```
error[E0478]: lifetime bound not satisfied
   --> f202.rs:2:12
    |
2   |     value: Box<dyn std::any::Any + 'a>,
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: lifetime parameter instantiated with the lifetime `'a` as defined here
   --> f202.rs:1:14
    |
1   | struct Hello<'a> {
    |              ^^
note: but lifetime parameter must outlive the static lifetime
   --> /home/gh-estebank/rust/library/core/src/any.rs:113:16
    |
113 | pub trait Any: 'static {
    |                ^^^^^^^
```

Partially address #33652.
2024-08-21 16:40:15 +00:00
Matthias Krüger
9bb17d345a
Rollup merge of #129281 - Nadrieril:tweak-unreachable-lint-wording, r=estebank
Tweak unreachable lint wording

Some tweaks to the notes added in https://github.com/rust-lang/rust/pull/128034.

r? `@estebank`
2024-08-21 18:15:03 +02:00
Matthias Krüger
7da4b2d82a
Rollup merge of #129179 - compiler-errors:cfi-erase-transparent, r=davidtwco
CFI: Erase regions when projecting ADT to its transparent non-1zst field

The output from `FieldDef::ty` (or `TyCtxt::type_of`) may have free regions (well, `'static`) -- erase it.

Fixes #129169
Fixes #123685
2024-08-21 18:15:02 +02:00
Matthias Krüger
d502b1c8e4
Rollup merge of #129270 - compiler-errors:inner-generics-shadowing, r=petrochenkov
Don't consider locals to shadow inner items' generics

We don't want to consider the bindings from a `RibKind::Module` itself, because for an inner item that module will contain the local bindings from the function body or wherever else the inner item is being defined.

Fixes #129265

r? petrochenkov
2024-08-20 22:21:57 +02:00
Matthias Krüger
2e58d62fec
Rollup merge of #128932 - bvanjoi:issue-128813, r=petrochenkov
skip updating when external binding is existed

Fixes #128813

For following code:

```rs
extern crate core;

fn f() {
    use ::core;
}

macro_rules! m {
    () => {
        extern crate std as core;
    };
}

m!();

fn main() {}
```

- In the first loop, we define `extern crate core` and `use ::core` will be referred to `core` (yes, it does not consider if there are some macros that are not expanded. Ideally, this should be delayed if there are some unexpanded macros in the root, but I didn't change it like that because it seems like a huge change).
- Then `m` is expanded, which makes `extern_prelude('core')` return `std` rather than `core`, causing the inconsistency.

r? `@petrochenkov`
2024-08-20 22:21:56 +02:00
Nadrieril
f30392a985 Move the "matches no value" note to be a span label 2024-08-20 21:53:47 +02:00
Ding Xiang Fei
ef25fbd0b4
lint on tail expr drop order change in Edition 2024 2024-08-21 01:05:21 +08:00
bohan
df019a9f46 skip updating when external binding is existed 2024-08-20 20:34:13 +08:00
bors
a971212545 Auto merge of #127672 - compiler-errors:precise-capturing, r=spastorino
Stabilize opaque type precise capturing (RFC 3617)

This PR partially stabilizes opaque type *precise capturing*, which was specified in [RFC 3617](https://github.com/rust-lang/rfcs/pull/3617), and whose syntax was amended by FCP in [#125836](https://github.com/rust-lang/rust/issues/125836).

This feature, as stabilized here, gives us a way to explicitly specify the generic lifetime parameters that an RPIT-like opaque type captures.  This solves the problem of overcapturing, for lifetime parameters in these opaque types, and will allow the Lifetime Capture Rules 2024 ([RFC 3498](https://github.com/rust-lang/rfcs/pull/3498)) to be fully stabilized for RPIT in Rust 2024.

### What are we stabilizing?

This PR stabilizes the use of a `use<'a, T>` bound in return-position impl Trait opaque types.  Such a bound fully specifies the set of generic parameters captured by the RPIT opaque type, entirely overriding the implicit default behavior.  E.g.:

```rust
fn does_not_capture<'a, 'b>() -> impl Sized + use<'a> {}
//                               ~~~~~~~~~~~~~~~~~~~~
//                This RPIT opaque type does not capture `'b`.
```

The way we would suggest thinking of `impl Trait` types *without* an explicit `use<..>` bound is that the `use<..>` bound has been *elided*, and that the bound is filled in automatically by the compiler according to the edition-specific capture rules.

All non-`'static` lifetime parameters, named (i.e. non-APIT) type parameters, and const parameters in scope are valid to name, including an elided lifetime if such a lifetime would also be valid in an outlives bound, e.g.:

```rust
fn elided(x: &u8) -> impl Sized + use<'_> { x }
```

Lifetimes must be listed before type and const parameters, but otherwise the ordering is not relevant to the `use<..>` bound.  Captured parameters may not be duplicated.  For now, only one `use<..>` bound may appear in a bounds list.  It may appear anywhere within the bounds list.

### How does this differ from the RFC?

This stabilization differs from the RFC in one respect: the RFC originally specified `use<'a, T>` as syntactically part of the RPIT type itself, e.g.:

```rust
fn capture<'a>() -> impl use<'a> Sized {}
```

However, settling on the final syntax was left as an open question.  T-lang later decided via FCP in [#125836](https://github.com/rust-lang/rust/issues/125836) to treat `use<..>` as a syntactic bound instead, e.g.:

```rust
fn capture<'a>() -> impl Sized + use<'a> {}
```

### What aren't we stabilizing?

The key goal of this PR is to stabilize the parts of *precise capturing* that are needed to enable the migration to Rust 2024.

There are some capabilities of *precise capturing* that the RFC specifies but that we're not stabilizing here, as these require further work on the type system.  We hope to lift these limitations later.

The limitations that are part of this PR were specified in the [RFC's stabilization strategy](https://rust-lang.github.io/rfcs/3617-precise-capturing.html#stabilization-strategy).

#### Not capturing type or const parameters

The RFC addresses the overcapturing of type and const parameters; that is, it allows for them to not be captured in opaque types.  We're not stabilizing that in this PR.  Since all in scope generic type and const parameters are implicitly captured in all editions, this is not needed for the migration to Rust 2024.

For now, when using `use<..>`, all in scope type and const parameters must be nameable (i.e., APIT cannot be used) and included as arguments.  For example, this is an error because `T` is in scope and not included as an argument:

```rust
fn test<T>() -> impl Sized + use<> {}
//~^ ERROR `impl Trait` must mention all type parameters in scope in `use<...>`
```

This is due to certain current limitations in the type system related to how generic parameters are represented as captured (i.e. bivariance) and how inference operates.

We hope to relax this in the future, and this stabilization is forward compatible with doing so.

#### Precise capturing for return-position impl Trait **in trait** (RPITIT)

The RFC specifies precise capturing for RPITIT.  We're not stabilizing that in this PR.  Since RPITIT already adheres to the Lifetime Capture Rules 2024, this isn't needed for the migration to Rust 2024.

The effect of this is that the anonymous associated types created by RPITITs must continue to capture all of the lifetime parameters in scope, e.g.:

```rust
trait Foo<'a> {
    fn test() -> impl Sized + use<Self>;
    //~^ ERROR `use<...>` precise capturing syntax is currently not allowed in return-position `impl Trait` in traits
}
```

To allow this involves a meaningful amount of type system work related to adding variance to GATs or reworking how generics are represented in RPITITs.  We plan to do this work separately from the stabilization.  See:

- https://github.com/rust-lang/rust/pull/124029

Supporting precise capturing for RPITIT will also require us to implement a new algorithm for detecting refining capture behavior.  This may involve looking through type parameters to detect cases where the impl Trait type in an implementation captures fewer lifetimes than the corresponding RPITIT in the trait definition, e.g.:

```rust
trait Foo {
    fn rpit() -> impl Sized + use<Self>;
}

impl<'a> Foo for &'a () {
    // This is "refining" due to not capturing `'a` which
    // is implied by the trait's `use<Self>`.
    fn rpit() -> impl Sized + use<>;

    // This is not "refining".
    fn rpit() -> impl Sized + use<'a>;
}
```

This stabilization is forward compatible with adding support for this later.

### The technical details

This bound is purely syntactical and does not lower to a [`Clause`](https://doc.rust-lang.org/1.79.0/nightly-rustc/rustc_middle/ty/type.ClauseKind.html) in the type system.  For the purposes of the type system (and for the types team's curiosity regarding this stabilization), we have no current need to represent this as a `ClauseKind`.

Since opaques already capture a variable set of lifetimes depending on edition and their syntactical position (e.g. RPIT vs RPITIT), a `use<..>` bound is just a way to explicitly rather than implicitly specify that set of lifetimes, and this only affects opaque type lowering from AST to HIR.

### FCP plan

While there's much discussion of the type system here, the feature in this PR is implemented internally as a transformation that happens before lowering to the type system layer.  We already support impl Trait types partially capturing the in scope lifetimes; we just currently only expose that implicitly.

So, in my (errs's) view as a types team member, there's nothing for types to weigh in on here with respect to the implementation being stabilized, and I'd suggest a lang-only proposed FCP (though we'll of course CC the team below).

### Authorship and acknowledgments

This stabilization report was coauthored by compiler-errors and TC.

TC would like to acknowledge the outstanding and speedy work that compiler-errors has done to make this feature happen.

compiler-errors thanks TC for authoring the RFC, for all of his involvement in this feature's development, and pushing the Rust 2024 edition forward.

### Open items

We're doing some things in parallel here.  In signaling the intention to stabilize, we want to uncover any latent issues so we can be sure they get addressed.  We want to give the maximum time for discussion here to happen by starting it while other remaining miscellaneous work proceeds.  That work includes:

- [x] Look into `syn` support.
  - https://github.com/dtolnay/syn/issues/1677
  - https://github.com/dtolnay/syn/pull/1707
- [x] Look into `rustfmt` support.
  - https://github.com/rust-lang/rust/pull/126754
- [x] Look into `rust-analyzer` support.
  - https://github.com/rust-lang/rust-analyzer/issues/17598
  - https://github.com/rust-lang/rust-analyzer/pull/17676
- [x] Look into `rustdoc` support.
  - https://github.com/rust-lang/rust/issues/127228
  - https://github.com/rust-lang/rust/pull/127632
  - https://github.com/rust-lang/rust/pull/127658
- [x] Suggest this feature to RfL (a known nightly user).
- [x] Add a chapter to the edition guide.
  - https://github.com/rust-lang/edition-guide/pull/316
- [x] Update the Reference.
  - https://github.com/rust-lang/reference/pull/1577

### (Selected) implementation history

* https://github.com/rust-lang/rfcs/pull/3498
* https://github.com/rust-lang/rfcs/pull/3617
* https://github.com/rust-lang/rust/pull/123468
* https://github.com/rust-lang/rust/issues/125836
* https://github.com/rust-lang/rust/pull/126049
* https://github.com/rust-lang/rust/pull/126753

Closes #123432.

cc `@rust-lang/lang` `@rust-lang/types`

`@rustbot` labels +T-lang +I-lang-nominated +A-impl-trait +F-precise_capturing

Tracking:

- https://github.com/rust-lang/rust/issues/123432

----

For the compiler reviewer, I'll leave some inline comments about diagnostics fallout :^)

r? compiler
2024-08-20 10:42:55 +00:00
Michael Goulet
78d0e08504 Don't consider RibKind::Module's bindings when checking generics shadowing 2024-08-19 17:24:27 -04:00
Nadrieril
36eced444e Cap the number of patterns pointed to by the lint 2024-08-19 21:57:40 +02:00
Nadrieril
efb28bdd90 Add a note with a link to explain empty types 2024-08-19 21:57:37 +02:00
Nadrieril
25964b541e Reword the "unreachable pattern" explanations 2024-08-19 21:39:57 +02:00
Matthias Krüger
7b245e4506
Rollup merge of #129235 - GoldsteinE:check-may-dangle, r=compiler-errors
Check that `#[may_dangle]` is properly applied

It's only valid when applied to a type or lifetime parameter in `Drop` trait implementation.

Tracking issue: https://github.com/rust-lang/rust/issues/34761
cc https://github.com/rust-lang/rust/issues/34761#issuecomment-1208185551
2024-08-19 20:14:57 +02:00
Matthias Krüger
5ba877c262
Rollup merge of #129223 - wafarm:fix-129215, r=compiler-errors
Fix wrong argument for `get_fn_decl`

Closes #129215 (seems to be introduced in #129168)
2024-08-19 20:14:57 +02:00
Matthias Krüger
5cb30b7e9d
Rollup merge of #129217 - jswrenn:transmute-lifetimes, r=compiler-errors
safe transmute: check lifetimes

Modifies `BikeshedIntrinsicFrom` to forbid lifetime extensions on references. This static check can be opted out of with the `Assume::lifetimes` flag.

Fixes #129097

Tracking Issue: https://github.com/rust-lang/rust/issues/99571

 r​? `@compiler-errors`
2024-08-19 20:14:56 +02:00
Trevor Gross
8a513f1720
Rollup merge of #129208 - veluca93:adt_const_fix, r=BoxyUwU
Fix order of normalization and recursion in const folding.

Fixes #126831.

Without this patch, type normalization is not always idempotent, which leads to all sorts of bugs in places that assume that normalizing a normalized type does nothing.

Tracking issue: https://github.com/rust-lang/rust/issues/95174

r? BoxyUwU
2024-08-18 23:41:49 -05:00
Trevor Gross
d21b6f2715
Rollup merge of #128084 - surechen:fix_125997_v1, r=cjgillot
Suggest adding Result return type for associated method in E0277.

Recommit #126515 because I messed up during rebase,

Suggest adding Result return type for associated method in E0277.

For following:

```rust
struct A;
impl A {
    fn test4(&self) {
        let mut _file = File::create("foo.txt")?;
        //~^ ERROR the `?` operator can only be used in a method
    }
```

Suggest:

```rust
impl A {
    fn test4(&self) -> Result<(), Box<dyn std::error::Error>> {
        let mut _file = File::create("foo.txt")?;
        //~^ ERROR the `?` operator can only be used in a method

    Ok(())
    }
}
```

For #125997

r? `@cjgillot`
2024-08-18 23:41:46 -05:00
Trevor Gross
f27a9b15d3
Rollup merge of #127679 - RalfJung:raw_ref_op, r=jieyouxu
Stabilize `raw_ref_op` (RFC 2582)

This stabilizes the syntax `&raw const $expr` and `&raw mut $expr`. It has existed unstably for ~4 years now, and has been exposed on stable via the `addr_of` and `addr_of_mut` macros since Rust 1.51 (released more than 3 years ago). I think it has become clear that these operations are here to stay. So it is about time we give them proper primitive syntax. This has two advantages over the macro:

- Being macros, `addr_of`/`addr_of_mut` could in theory do arbitrary magic with the expression on which they work. The only "magic" they actually do is using the argument as a place expression rather than as a value expression. Place expressions are already a subtle topic and poorly understood by many programmers; having this hidden behind a macro using unstable language features makes this even worse. Conversely, people do have an idea of what happens below `&`/`&mut`, so we can make the subtle topic a lot more approachable by connecting to existing intuition.
- The name `addr_of` is quite unfortunate from today's perspective, given that we have accepted provenance as a reality, which means that a pointer is *not* just an address. Strict provenance has a method, `addr`, which extracts the address of a pointer; using the term `addr` in two different ways is quite unfortunate. That's why this PR soft-deprecates `addr_of` -- we will wait a long time before actually showing any warning here, but we should start telling people that the "addr" part of this name is somewhat misleading, and `&raw` avoids that potential confusion.

In summary, this syntax improves developers' ability to conceptualize the operational semantics of Rust, while making a fundamental operation frequently used in unsafe code feel properly built in.

Possible questions to consider, based on the RFC and [this](https://github.com/rust-lang/rust/issues/64490#issuecomment-1163802912) great summary by `@CAD97:`

- Some questions are entirely about the semantics. The semantics are the same as with the macros so I don't think this should have any impact on this syntax PR. Still, for completeness' sake:
  - Should `&raw const *mut_ref` give a read-only pointer?
    - Tracked at: https://github.com/rust-lang/unsafe-code-guidelines/issues/257
    - I think ideally the answer is "no". Stacked Borrows says that pointer is read-only, but Tree Borrows says it is mutable.
  - What exactly does `&raw const (*ptr).field` require? Answered in [the reference](https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html): the arithmetic to compute the field offset follows the rules of `ptr::offset`, making it UB if it goes out-of-bounds. Making this a safe operation (using `wrapping_offset` rules) is considered too much of a loss for alias analysis.
- Choose a different syntax? I don't want to re-litigate the RFC. The only credible alternative that has been proposed is `&raw $place` instead of `&raw const $place`, which (IIUC) could be achieved by making `raw` a contextual keyword in a new edition. The type is named `*const T`, so the explicit `const` is consistent in that regard. `&raw expr` lacks the explicit indication of immutability. However, `&raw const expr` is quite a but longer than `addr_of!(expr)`.
- Shouldn't we have a completely new, better raw pointer type instead? Yes we all want to see that happen -- but I don't think we should block stabilization on that, given that such a nicer type is not on the horizon currently and given the issues with `addr_of!` mentioned above. (If we keep the `&raw $place` syntax free for this, we could use it in the future for that new type.)
- What about the lint the RFC talked about? It hasn't been implemented yet.  Given that the problematic code is UB with or without this stabilization, I don't think the lack of the lint should block stabilization.
  - I created an issue to track adding it: https://github.com/rust-lang/rust/issues/127724
- Other points from the "future possibilites of the RFC
  - "Syntactic sugar" extension: this has not been implemented. I'd argue this is too confusing, we should stick to what the RFC suggested and if we want to do anything about such expressions, add the lint.
  - Encouraging / requiring `&raw` in situations where references are often/definitely incorrect: this has been / is being implemented. On packed fields this already is a hard error, and for `static mut` a lint suggesting raw pointers is being rolled out.
  - Lowering of casts: this has been implemented. (It's also an invisible implementation detail.)
  - `offsetof` woes: we now have native `offset_of` so this is not relevant any more.

To be done before landing:

- [x] Suppress `unused_parens` lint around `&raw {const|mut}` expressions
  - See bottom of https://github.com/rust-lang/rust/pull/127679#issuecomment-2264073752 for rationale
  - Implementation: https://github.com/rust-lang/rust/pull/128782
- [ ] Update the Reference.
  - https://github.com/rust-lang/reference/pull/1567

Fixes https://github.com/rust-lang/rust/issues/64490

cc `@rust-lang/lang` `@rust-lang/opsem`

try-job: x86_64-msvc
try-job: test-various
try-job: dist-various-1
try-job: armhf-gnu
try-job: aarch64-apple
2024-08-18 23:41:46 -05:00
Wafarm
da7dd434c8
Fix wrong argument for get_fn_decl 2024-08-19 11:08:51 +08:00
bors
d0293c6cf2 Auto merge of #125854 - beetrees:zst-arg-abi, r=estebank
Move ZST ABI handling to `rustc_target`

Currently, target specific handling of ZST function call ABI (specifically passing them indirectly instead of ignoring them) is handled in `rustc_ty_utils`, whereas all other target specific function call ABI handling is located in `rustc_target`. This PR moves the ZST handling to `rustc_target` so that all the target-specific function call ABI handling is in one place. In the process of doing so, this PR fixes #125850 by ensuring that ZST arguments are always correctly ignored in the x86-64 `"sysv64"` ABI; any code which would be affected by this fix would have ICEd before this PR. Tests are also added using `#[rustc_abi(debug)]` to ensure this behaviour does not regress.

Fixes #125850
2024-08-18 22:15:41 +00:00
Jack Wrenn
17995d5cc2 safe transmute: forbid reference lifetime extension
Modifies `BikeshedIntrinsicFrom` to forbid lifetime extensions on
references. This static check can be opted out of with the
`Assume::lifetimes` flag.

Fixes #129097
2024-08-18 18:31:06 +00:00
Ralf Jung
79503dd742 stabilize raw_ref_op 2024-08-18 19:46:53 +02:00
Goldstein
df6cb954bb
Fix wording of misapplied must_not_suspend error 2024-08-18 20:32:04 +03:00
Goldstein
3a9bf45513
Check that #[may_dangle] is properly applied
It's only valid when applied to a type or lifetime parameter
in `Drop` trait implementation.
2024-08-18 20:32:00 +03:00
bors
37d56daac6 Auto merge of #128771 - carbotaniuman:stabilize_unsafe_attr, r=nnethercote
Stabilize `unsafe_attributes`

# Stabilization report

## Summary

This is a tracking issue for the RFC 3325: unsafe attributes

We are stabilizing `#![feature(unsafe_attributes)]`,  which makes certain attributes considered 'unsafe', meaning that they must be surrounded by an `unsafe(...)`, as in `#[unsafe(no_mangle)]`.

RFC: rust-lang/rfcs#3325
Tracking issue: #123757

## What is stabilized

### Summary of stabilization

Certain attributes will now be designated as unsafe attributes, namely, `no_mangle`, `export_name`, and `link_section` (stable only), and these attributes will need to be called by surrounding them in `unsafe(...)` syntax. On editions prior to 2024, this is simply an edition lint, but it will become a hard error in 2024. This also works in `cfg_attr`, but `unsafe` is not allowed for any other attributes, including proc-macros ones.

```rust
#[unsafe(no_mangle)]
fn a() {}

#[cfg_attr(any(), unsafe(export_name = "c"))]
fn b() {}
```

For a table showing the attributes that were considered to be included in the list to require unsafe, and subsequent reasoning about why each such attribute was or was not included, see [this comment here](https://github.com/rust-lang/rust/pull/124214#issuecomment-2124753464)

## Tests

The relevant tests are in `tests/ui/rust-2024/unsafe-attributes` and `tests/ui/attributes/unsafe`.
2024-08-17 22:48:42 +00:00
Luca Versari
7fd62320fe Fix order of normalization and recursion in const folding.
Fixes #126831.

Without this patch, type normalization is not always idempotent, which
leads to all sorts of bugs in places that assume that normalizing a
normalized type does nothing.
2024-08-18 00:07:41 +02:00
bors
feeba198f2 Auto merge of #128792 - compiler-errors:foreign-sig, r=spastorino
Use `FnSig` instead of raw `FnDecl` for `ForeignItemKind::Fn`, fix ICE for `Fn` trait error on safe foreign fn

Let's use `hir::FnSig` instead of `hir::FnDecl + hir::Safety` for `ForeignItemKind::Fn`. This consolidates some handling code between normal fns and foreign fns.

Separetly, fix an ICE where we weren't handling `Fn` trait errors for safe foreign fns.

If perf is bad for the first commit, I can rework the ICE fix to not rely on it. But if perf is good, I prefer we fix and clean up things all at once 👍

r? spastorino

Fixes #128764
2024-08-17 19:35:01 +00:00
Michael Goulet
84044cd50f Bless test fallout 2024-08-17 12:43:25 -04:00
Michael Goulet
eae5b5c6e7 Stabilize opaque type precise capturing 2024-08-17 12:33:29 -04:00
Matthias Krüger
ddbbda47eb
Rollup merge of #129168 - BoxyUwU:mismatched_ty_correct_id, r=compiler-errors
Return correct HirId when finding body owner in diagnostics

Fixes #129145
Fixes #128810

r? ```@compiler-errors```

```rust
fn generic<const N: u32>() {}

trait Collate<const A: u32> {
    type Pass;
    fn collate(self) -> Self::Pass;
}

impl<const B: u32> Collate<B> for i32 {
    type Pass = ();
    fn collate(self) -> Self::Pass {
        generic::<{ true }>()
        //~^ ERROR: mismatched types
    }
}
```

When type checking the `{ true }` anon const we would error with a type mismatch. This then results in diagnostics code attempting to check whether its due to a type mismatch with the return type. That logic was implemented by walking up the hir until we reached the body owner, except instead of using the `enclosing_body_owner` function it special cased various hir nodes incorrectly resulting in us walking out of the anon const and stopping at `fn collate` instead.

This then resulted in diagnostics logic inside of the anon consts `ParamEnv` attempting to do trait solving involving the `<i32 as Collate<B>>::Pass` type which ICEs because it is in the wrong environment.

I have rewritten this function to just walk up until it hits the `enclosing_body_owner` and made some other changes since I found this pretty hard to read/understand. Hopefully it's easier to understand now, it also makes it more obvious that this is not implemented in a very principled way and is definitely missing cases :)
2024-08-17 18:18:19 +02:00
Matthias Krüger
cfeded47a4
Rollup merge of #128989 - s7tya:check-linkage-attribute-pos, r=petrochenkov
Emit an error for invalid use of the linkage attribute

fixes #128486

Currently, the use of the linkage attribute for Mod, Impl,... is incorrectly permitted. This PR will correct this issue by generating errors, and I've also added some UI test cases for it.

Related: #128552.
2024-08-17 18:18:18 +02:00
bors
426a60abc2 Auto merge of #128598 - RalfJung:float-comments, r=workingjubilee
float to/from bits and classify: update for float semantics RFC

With https://github.com/rust-lang/rfcs/pull/3514 having been accepted, it is clear that hardware which e.g. flushes subnormal to zero is just non-conformant from a Rust perspective -- this is a hardware bug, or maybe an LLVM backend bug (where LLVM doesn't lower floating-point ops in a way that they have the standardized behavior). So update the comments here to make it clear that we don't have to do any of this, we're just being nice.

Also remove the subnormal/NaN checks from the (unstable) const-version of to/from-bits; they are not needed since we decided with the aforementioned RFC that it is okay to get a different result at const-time and at run-time.

r? `@workingjubilee` since I think you wrote many of the comments I am editing here.
2024-08-17 09:13:13 +00:00
Ralf Jung
5f33085a7f more clear NAN names and fix broken_floats logic
Co-authored-by: Jubilee <46493976+workingjubilee@users.noreply.github.com>
2024-08-17 10:26:59 +02:00
Ralf Jung
53e1a2ee46 disable problematic float-conv tests in i586 targets
also fix typo in const-float-bits-conv
2024-08-17 10:26:53 +02:00
Shina
3c8dad152b Emit an error for invalid use of the linkage attribute 2024-08-17 15:03:20 +09:00