Commit graph

819 commits

Author SHA1 Message Date
Guillaume Gomez
3c860e3764
Rollup merge of #142148 - workingjubilee:dont-ice-on-force-warn, r=Urgau
compiler: Treat ForceWarning as a Warning for diagnostic level

This silences an ICE.

No idea if this is the correct solution though tbh.

Fixes rust-lang/rust#142144
2025-06-07 22:22:59 +02:00
Guillaume Gomez
c475ad097f
Rollup merge of #141661 - Urgau:deny-dangerous_implicit_autorefs, r=traviscross
Make the `dangerous_implicit_autorefs` lint deny-by-default

I intended for the `dangerous_implicit_autorefs` lint to be deny-by-default, the [T-lang nomination comment](https://github.com/rust-lang/rust/pull/123239#issuecomment-2727551097) even clearly mentioned deny-by-default, but somehow I and other missed that it is only warn-by-default.

I think the lint should still be deny-by-default as the implicit aliasing requirements can be quite dangerous.

In any-case, opening this PR for T-lang awareness.

`@rustbot` label +I-lang-nominated +T-lang
r? `@traviscross`
2025-06-07 22:22:57 +02:00
Guillaume Gomez
2c8a9cccd9
Rollup merge of #140560 - Urgau:test_attr-module-level, r=GuillaumeGomez
Allow `#![doc(test(attr(..)))]` everywhere

This PR adds the ability to specify [`#![doc(test(attr(..)))]`](https://doc.rust-lang.org/nightly/rustdoc/write-documentation/the-doc-attribute.html#testattr) ~~at module level~~ everywhere in addition to allowing it at crate-root.

This is motivated by a recent PR #140323 (by ````@tgross35)```` where we have to duplicate 2 attributes to every single `f16` and `f128` doctests, by allowing `#![doc(test(attr(..)))]` at module level (and everywhere else) we can omit them entirely and just have (in both module):

```rust
#![doc(test(attr(feature(cfg_target_has_reliable_f16_f128))))]
#![doc(test(attr(expect(internal_features))))]
```

Those new attributes are appended to the one found at crate-root or at a previous module. Those "global" attributes are compatible with merged doctests (they already were before).

Given the small addition that this is, I'm proposing to insta-stabilize it, but I can feature-gate it if preferred.

Best reviewed commit by commit.

r? ````@GuillaumeGomez````
2025-06-07 22:22:55 +02:00
Jubilee Young
5bab0d2e66 compiler: Treat ForceWarning as a Warning for diagnostic level
This silences an ICE.
2025-06-07 00:49:29 -07:00
bors
ccf3198de3 Auto merge of #138677 - shepmaster:consistent-elided-lifetime-syntax, r=traviscross,jieyouxu
Add a new `mismatched-lifetime-syntaxes` lint

The lang-team [discussed this](https://hackmd.io/nf4ZUYd7Rp6rq-1svJZSaQ) and I attempted to [summarize](https://github.com/rust-lang/rust/pull/120808#issuecomment-2701863833) their decision. The summary-of-the-summary is:

- Using two different kinds of syntax for elided lifetimes is confusing. In rare cases, it may even [lead to unsound code](https://github.com/rust-lang/rust/issues/48686)! Some examples:

    ```rust
    // Lint will warn about these
    fn(v: ContainsLifetime) -> ContainsLifetime<'_>;
    fn(&'static u8) -> &u8;
    ```

- Matching up references with no lifetime syntax, references with anonymous lifetime syntax, and paths with anonymous lifetime syntax is an exception to the simplest possible rule:

    ```rust
    // Lint will not warn about these
    fn(&u8) -> &'_ u8;
    fn(&'_ u8) -> &u8;
    fn(&u8) -> ContainsLifetime<'_>;
    ```

- Having a lint for consistent syntax of elided lifetimes will make the [future goal](https://github.com/rust-lang/rust/issues/91639) of warning-by-default for paths participating in elision much simpler.

---

This new lint attempts to accomplish the goal of enforcing consistent syntax. In the process, it supersedes and replaces the existing `elided-named-lifetimes` lint, which means it starts out life as warn-by-default.
2025-06-05 19:49:30 +00:00
bors
81a964c23e Auto merge of #142033 - matthiaskrgr:rollup-99lvg0j, r=matthiaskrgr
Rollup of 11 pull requests

Successful merges:

 - rust-lang/rust#141890 (Add link to correct documentation in htmldocck.py)
 - rust-lang/rust#141932 (Fix for async drop inside async gen fn)
 - rust-lang/rust#141960 (Use non-2015 edition paths in tests that do not test for their resolution)
 - rust-lang/rust#141968 (Run wfcheck in one big loop instead of per module)
 - rust-lang/rust#141969 (Triagebot: Remove `assign.users_on_vacation`)
 - rust-lang/rust#141985 (Ensure query keys are printed with reduced queries)
 - rust-lang/rust#141999 (Visit the ident in `PreciseCapturingNonLifetimeArg`.)
 - rust-lang/rust#142005 (Change `tag_field` to `FieldIdx` in `Variants::Multiple`)
 - rust-lang/rust#142017 (Fix incorrect use of "recommend" over "recommended")
 - rust-lang/rust#142024 (Don't refer to 'this tail expression' in expansion.)
 - rust-lang/rust#142025 (Don't refer to 'local binding' in extern macro.)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-06-05 00:30:08 +00:00
Matthias Krüger
be2d382158
Rollup merge of #141960 - ferrocene:lw/2015-paths2, r=compiler-errors
Use non-2015 edition paths in tests that do not test for their resolution

This allows for testing these tests on editions other than 2015

Follow up to https://github.com/rust-lang/rust/pull/141888
2025-06-04 19:50:21 +02:00
Jake Goulding
d35ad94849 Replace elided_named_lifetimes with mismatched_lifetime_syntaxes 2025-06-04 10:40:04 -04:00
Matthias Krüger
820971581a
Rollup merge of #141959 - ferrocene:lw/2015-edition-directives2, r=compiler-errors
Add more missing 2015 edition directives

These tests specifically test 2015 edition behavior, so ensure that they can only be run with this edition
2025-06-04 16:24:11 +02:00
Matthias Krüger
c5efc6aada
Rollup merge of #137306 - tgross35:remove-i128-u128-improper-ctypes, r=traviscross,workingjubilee
Remove `i128` and `u128` from `improper_ctypes_definitions`

Rust's 128-bit integers have historically been incompatible with C [1]. However, there have been a number of changes in Rust and LLVM that mean this is no longer the case:

* Incorrect alignment of `i128` on x86 [1]: adjusting Rust's alignment proposed at https://github.com/rust-lang/compiler-team/issues/683, implemented at https://github.com/rust-lang/rust/pull/116672.
* LLVM version of the above: resolved in LLVM, including ABI fix. Present in LLVM18 (our minimum supported version).
* Incorrect alignment of `i128` on 64-bit PowerPC, SPARC, and MIPS [2]: Rust's data layouts adjusted at https://github.com/rust-lang/rust/pull/132422, https://github.com/rust-lang/rust/pull/132741, https://github.com/rust-lang/rust/pull/134115.
* LLVM version of the above: done in LLVM 20 https://github.com/llvm/llvm-project/issues/102783.
* Incorrect return convention of `i128` on Windows: adjusted to match GCC and Clang at https://github.com/rust-lang/rust/pull/134290.

At https://github.com/rust-lang/lang-team/issues/255#issuecomment-2088855084, the lang team considered it acceptable to remove `i128` from `improper_ctypes_definitions` if the LLVM version is known to be compatible. Time has elapsed since then and we have dropped support for LLVM versions that do not have the x86 fixes, meaning a per-llvm-version lint should no longer be necessary. The PowerPC, SPARC, and MIPS changes only came in LLVM 20 but since Rust's datalayouts have also been updated to match, we will be using the correct alignment regardless of LLVM version.

`repr(i128)` was added to this lint in https://github.com/rust-lang/rust/pull/138282, but is also removed here.

Part of the decision is that `i128` should match `__int128` in C on platforms that provide it, which documentation is updated to indicate. We will not guarantee that `i128` matches `_BitInt(128)` since that can be different from `__int128`. Some platforms (usually 32-bit) do not provide `__int128`; if any ABIs are extended in the future to define it, we will need to make sure that our ABI matches.

Closes: https://github.com/rust-lang/rust/issues/134288

[1]: https://github.com/rust-lang/rust/issues/54341
[2]: https://github.com/rust-lang/rust/issues/128950
2025-06-04 07:54:31 +02:00
Lukas Wirth
eae7fe1bdb Use non-2015 edition paths in tests that do not test for their resolution
This allows for testing these tests on editions other than 2015
2025-06-03 13:35:31 +02:00
Lukas Wirth
49969468b5 Add missing 2015 edition directives
These tests specifically test 2015 edition behavior, so ensure that they can only be run with this edition
2025-06-03 11:45:58 +02:00
Matthias Krüger
282c6654a0
Rollup merge of #141793 - Kivooeo:test-reform, r=jieyouxu
`tests/ui`: A New Order [1/N]

not sure if i should say something about changes here, just part of rust-lang/rust#133895

but this is my very first time doing something like this, id love to keep contributing in this area later on, so any feedback is appreciated

also should say that im going to squash it after agreement on changes

r? `@jieyouxu`

mind if i name this PR series like "`tests/ui`: A New Order [N/N]", im not sure if it fits the project tone, so id like your approval first — but i think it sounds really neat (Star Wars reference)

this could be a first part :)
2025-05-31 18:51:49 +02:00
Kivooeo
afc64242b6 cleaned up some tests 2025-05-31 19:49:19 +05:00
Matthias Krüger
896be667b8
Rollup merge of #141407 - mu001999-contrib:dead-code/refactor, r=petrochenkov
Refactor the two-phase check for impls and impl items

Refactor the two-phase dead code check to make the logic clearer and simpler:
1. adding assoc fn and impl into `unsolved_items` directly during the initial construction of the worklist
2. converge the logic of checking whether assoc fn and impl are used to `item_should_be_checked`, and the item is considered used only when its corresponding trait and Self adt are used

This PR only refactors as much as possible to avoid affecting the original functions. However, due to the adjustment of the order of checks, the test results are slightly different, but overall, there is no regression problem

Fixes rust-lang/rust#127911
Fixes rust-lang/rust#128839

Extracted from https://github.com/rust-lang/rust/pull/128637.
r? petrochenkov

try-job: dist-aarch64-linux
2025-05-30 07:01:29 +02:00
Matthias Krüger
7aba37da44
Rollup merge of #133823 - estebank:issue-56328, r=petrochenkov
Use `cfg_attr_trace` in AST with a placeholder attribute for accurate suggestion

In rust-lang/rust#138515, we insert a placeholder attribute so that checks for attributes can still know about the placement of `cfg` attributes. When we suggest removing items with `cfg_attr`s (fix rust-lang/rust#56328) and make them verbose. We tweak the wording of the existing "unused `extern crate`" lint.

```
warning: unused `extern crate`
  --> $DIR/removing-extern-crate.rs:9:1
   |
LL | extern crate removing_extern_crate as foo;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
   |
note: the lint level is defined here
  --> $DIR/removing-extern-crate.rs:6:9
   |
LL | #![warn(rust_2018_idioms)]
   |         ^^^^^^^^^^^^^^^^
   = note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
help: remove the unused `extern crate`
   |
LL - #[cfg_attr(test, macro_use)]
LL - extern crate removing_extern_crate as foo;
   |
```

r? `@petrochenkov`

try-job: x86_64-gnu-aux
2025-05-30 07:01:27 +02:00
Trevor Gross
0cba7fb6f6 Remove i128 and u128 from improper_ctypes_definitions
Rust's 128-bit integers have historically been incompatible with C [1].
However, there have been a number of changes in Rust and LLVM that
mean this is no longer the case:

* Incorrect alignment of `i128` on x86 [1]: adjusting Rust's alignment
  proposed at https://github.com/rust-lang/compiler-team/issues/683,
  implemented at https://github.com/rust-lang/rust/pull/116672.
* LLVM version of the above: resolved in LLVM, including ABI fix.
  Present in LLVM18 (our minimum supported version).
* Incorrect alignment of `i128` on 64-bit PowerPC, SPARC, and MIPS [2]:
  Rust's data layouts adjusted at
  https://github.com/rust-lang/rust/pull/132422,
  https://github.com/rust-lang/rust/pull/132741,
  https://github.com/rust-lang/rust/pull/134115.
* LLVM version of the above: done in LLVM 20
  https://github.com/llvm/llvm-project/issues/102783.
* Incorrect return convention of `i128` on Windows: adjusted to match
  GCC and Clang at https://github.com/rust-lang/rust/pull/134290.

At [3], the lang team considered it acceptable to remove `i128` from
`improper_ctypes_definitions` if the LLVM version is known to be
compatible. Time has elapsed since then and we have dropped support for
LLVM versions that do not have the x86 fixes, meaning a per-llvm-version
lint should no longer be necessary. The PowerPC, SPARC, and MIPS changes
only came in LLVM 20 but since Rust's datalayouts have also been updated
to match, we will be using the correct alignment regardless of LLVM
version.

`repr(i128)` was added to this lint in [4], but is also removed here.

Part of the decision is that `i128` should match `__int128` in C on
platforms that provide it, which documentation is updated to indicate.
We will not guarantee that `i128` matches `_BitInt(128)` since that can
be different from `__int128`. Some platforms (usually 32-bit) do not
provide `__int128`; if any ABIs are extended in the future to define it,
we will need to make sure that our ABI matches.

Closes: https://github.com/rust-lang/rust/issues/134288
Closes: https://github.com/rust-lang/rust/issues/128950

[1]: https://github.com/rust-lang/rust/issues/54341
[2]: https://github.com/rust-lang/rust/issues/128950
[3]: https://github.com/rust-lang/lang-team/issues/255#issuecomment-2088855084
[4]: https://github.com/rust-lang/rust/pull/138282
2025-05-29 12:55:26 +00:00
Mu001999
6eb6010368 Add test for issue 127911 and 128839 2025-05-29 20:51:51 +08:00
Esteban Küber
f80e3ac4ed Use cfg_attr AST placeholder AST cfg_attr_trace for diagnostics
PR 138515, we insert a placeholder attribute so that checks for attributes can still know about the placement of `cfg` attributes. When we suggest removing items with `cfg_attr`s (fix Issue 56328) and make them verbose. We tweak the wording of the existing "unused `extern crate`" lint.

```
warning: unused extern crate
  --> $DIR/removing-extern-crate.rs:9:1
   |
LL | extern crate removing_extern_crate as foo;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
   |
note: the lint level is defined here
  --> $DIR/removing-extern-crate.rs:6:9
   |
LL | #![warn(rust_2018_idioms)]
   |         ^^^^^^^^^^^^^^^^
   = note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
help: remove the unused `extern crate`
   |
LL - #[cfg_attr(test, macro_use)]
LL - extern crate removing_extern_crate as foo;
LL +
   |
```
2025-05-29 10:24:23 +00:00
beetrees
467eeabbb5
Stabilise repr128 2025-05-28 15:14:34 +01:00
Urgau
d851cfab33 Make the dangerous_implicit_autorefs lint deny-by-default 2025-05-27 21:14:48 +02:00
Mu001999
f83ecd8270 Refactor the two-phase check for impls and impl items 2025-05-27 22:03:21 +08:00
Michael Goulet
a0d77f37f3
Rollup merge of #141536 - Urgau:ambi_wide_ptr-cmp-diag, r=fee1-dead
Improve `ambiguous_wide_pointer_comparisons` lint compare diagnostics

This PR improves the `ambiguous_wide_pointer_comparisons` lint compare diagnostics: `cmp`/`partial_cmp`, but also the operators `<`/`>`/`>=`/`<=`, by:
1. removing the reference to `std::ptr::addr_eq` which only works for equality
2. and adding an `#[expect]` suggestion for keeping the current behavior

Fixes rust-lang/rust#141510
2025-05-27 13:01:36 +02:00
许杰友 Jieyou Xu (Joe)
bca4279457
Rollup merge of #141550 - Urgau:unused_braces-attrs, r=chenyukang
Fix `unused_braces` lint suggestion when encountering attributes

This PR fixes the `unused_braces` lint suggestion when encountering attributes by not removing them in the suggestion.

Fixes rust-lang/rust#141549
2025-05-27 01:29:22 +08:00
Urgau
4765fd6b76 Fix unused_braces lint suggestion when encountering attributes 2025-05-25 18:17:43 +02:00
Urgau
77e295c39c Improve ambiguous_wide_pointer_comparisons lint compare diagnostics 2025-05-25 17:08:58 +02:00
Urgau
316e62a058 Allow #![doc(test(attr(..)))] at every level 2025-05-22 20:12:50 +02:00
Matthias Krüger
3216098e53
Rollup merge of #140218 - fmease:hirtylo-clean-up-path-low, r=compiler-errors
HIR ty lowering: Clean up & refactor the lowering of type-relative paths

While rebasing #126651 I realized that HIR ty lowering could benefit from some *spring cleaning* now that it's been extended to handle RTN and mGCA paths.

More seriously, similar to my merged PR #118668 which unified the handling of all *associated item constraints* (assoc ty, const (ACE) & fn (RTN)), this PR (commit https://github.com/rust-lang/rust/pull/140218/commits/695fcf517d8864b4812225643ef8cfc036ba9f61) partially[^1] deduplicates the resolution code for all *type-relative paths* (assoc ty, const (mGCA) & fn (RTN)).

**Why**? DRY'ing that part of the code means PR #126651 will automatically support RTN paths like `Ty::AssocTy::assoc_fn(..)` and it also implies shared diagnostic code and thus better diagnostics for RTN.

---

The other commits represent cleanups, renamings, moves. More notably, I've renamed path lowering methods to be a lot more descriptive, so ones lowering `QPath(Resolved)` paths now have `_resolved_` in their name and ones lowering `QPath(TypeRelative)` paths now have `_type_relative_` in their name. This should make it stupidly obvious what their purpose is.

---

Best reviewed commit by commit. The changes are close to trivial but the diff might make it look hairier.
r? compiler-errors

[^1]: Sadly, I couldn't unify as much compared to the other PR without introducing unnecessary `unreachable!()`s or rendering the code otherwise illegible with flags and micro helper traits.
2025-05-22 16:02:28 +02:00
Urgau
9b3abe79d7 Use more subdiagnostics and reword the overloaded deref note 2025-05-14 23:53:40 +02:00
Urgau
ac1df15f86 Improve dangerous_implicit_aurorefs diagnostic output 2025-05-14 18:58:38 +02:00
xizheyin
88c1796384 Use span before macro expansion in lint for-loops-over-falibles
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-05-08 21:17:33 +08:00
xizheyin
c0f0b5157f
Add ui test for for-loops-over-falibles
Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
2025-05-08 21:17:28 +08:00
Jacob Pratt
60a4b939a3
Rollup merge of #134273 - RalfJung:de-stabilize-bench, r=ibraheemdev,traviscross
de-stabilize bench attribute

This has been soft-unstable since forever (https://github.com/rust-lang/rust/pull/64066), and shown in future-compat reports since Rust 1.77 (https://github.com/rust-lang/rust/pull/116274).

The feature covering `bench` itself is tracked in https://github.com/rust-lang/rust/issues/50297, which has been closed despite still having active feature gates referencing it.

Cc `@rust-lang/libs-api`
2025-05-07 00:29:20 +00:00
León Orell Valerian Liehr
8c37c8c3e6
Preserve generic args in suggestions for ambiguous associated items
Most notably, this preserves the `(..)` of ambiguous RTN paths.
2025-05-06 17:04:03 +02:00
Michael Goulet
45598de704 Do not gather local all together at the beginning of typeck 2025-05-05 14:27:09 +00:00
Vadim Petrochenkov
56d6b4e427 compiletest: Support matching on non-json lines in compiler output
and migrate most of remaining `error-pattern`s to it.
2025-05-04 18:27:45 +03:00
Stuart Cook
96852e2494
Rollup merge of #134034 - bvanjoi:issue-131655, r=petrochenkov
handle paren in macro expand for let-init-else expr

Fixes #131655

This PR modifies the codegen logic of the macro expansion within `let-init-else` expression:
- Before: The expression `let xxx = (mac! {}) else {}` expands to `let xxx = (expanded_ast) else {}`.
- After: The same expression expands to `let xxx = expanded_ast else {}`.

An alternative solution to this issue could involve handling the source code directly when encountering unused parentheses in `let-init-else` expressions. However, this approach might be more cumbersome due to the absence of the necessary data structure.

r? `@petrochenkov`
2025-05-02 22:16:57 +10:00
Matthias Krüger
230215f890
Rollup merge of #140090 - Urgau:snake_case-fn-var, r=petrochenkov
Check bare function idents for non snake-case name

This PR adds the check required to lint on bare function idents for non snake-case name.

Reported at #140089.
cc `@theemathas`
2025-04-30 17:27:58 +02:00
bohan
e9d2fefe0c stop check paren if has different ctx 2025-04-30 01:29:44 +08:00
bors
25cdf1f674 Auto merge of #140388 - GuillaumeGomez:rollup-aj9o3ch, r=GuillaumeGomez
Rollup of 7 pull requests

Successful merges:

 - #140056 (Fix a wrong error message in 2024 edition)
 - #140220 (Fix detection of main function if there are expressions around it)
 - #140249 (Remove `weak` alias terminology)
 - #140316 (Introduce `BoxMarker` to improve pretty-printing correctness)
 - #140347 (ci: clean more disk space in codebuild)
 - #140349 (ci: use aws codebuild for the `dist-x86_64-linux` job)
 - #140379 (rustc-dev-guide subtree update)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-04-28 17:22:11 +00:00
bors
a932eb36f8 Auto merge of #123239 - Urgau:dangerous_implicit_autorefs, r=jdonszelmann,traviscross
Implement a lint for implicit autoref of raw pointer dereference - take 2

*[t-lang nomination comment](https://github.com/rust-lang/rust/pull/123239#issuecomment-2727551097)*

This PR aims at implementing a lint for implicit autoref of raw pointer dereference, it is based on #103735 with suggestion and improvements from https://github.com/rust-lang/rust/pull/103735#issuecomment-1370420305.

The goal is to catch cases like this, where the user probably doesn't realise it just created a reference.

```rust
pub struct Test {
    data: [u8],
}

pub fn test_len(t: *const Test) -> usize {
    unsafe { (*t).data.len() }  // this calls <[T]>::len(&self)
}
```

Since #103735 already went 2 times through T-lang, where they T-lang ended-up asking for a more restricted version (which is what this PR does), I would prefer this PR to be reviewed first before re-nominating it for T-lang.

----

Compared to the PR it is as based on, this PR adds 3 restrictions on the outer most expression, which must either be:
   1. A deref followed by any non-deref place projection (that intermediate deref will typically be auto-inserted)
   2. A method call annotated with `#[rustc_no_implicit_refs]`.
   3. A deref followed by a `addr_of!` or `addr_of_mut!`. See bottom of post for details.

There are several points that are not 100% clear to me when implementing the modifications:
 - ~~"4. Any number of automatically inserted deref/derefmut calls." I as never able to trigger this. Am I missing something?~~ Fixed
 - Are "index" and "field" enough?

----

cc `@JakobDegen` `@WaffleLapkin`
r? `@RalfJung`

try-job: dist-various-1
try-job: dist-various-2
2025-04-28 08:25:23 +00:00
yuk1ty
bffb7608ce Fix error message for static references or mutable references 2025-04-26 14:48:30 +09:00
Matthias Krüger
27eac4b6d3
Rollup merge of #138282 - beetrees:repr128-not-ffi-safe, r=oli-obk
Add `#[repr(u128)]`/`#[repr(i128)]` enums to `improper_ctypes_definitions`

This makes them warn whenever a plain `u128`/`i128` would. If the lang team decides to merge #137306 then this can be reverted.

Tracking issue: #56071
2025-04-24 17:19:43 +02:00
Matthias Krüger
53afa97eb7
Rollup merge of #136083 - bend-n:⃤⃤, r=lcnr
Suggest {to,from}_ne_bytes for transmutations between arrays and integers, etc

implements #136067

Rust has helper methods for many kinds of safe transmutes, for example integer<->bytes. This is a lint against using transmute for these cases.

```rs
fn bytes_at_home(x: [u8; 4]) -> u32 {
   transmute(x)
}

// other examples
transmute::<[u8; 2], u16>();
transmute::<[u8; 8], f64>();
transmute::<u32, [u8; 4]>();
transmute::<char, u32>();
transmute::<u32, char>();
```
It would be handy to suggest `u32::from_ne_bytes(x)`.
This is implemented for `[u8; _]` -> `{float int}`

This also implements the cases:
`fXX` <-> `uXX` = `{from_bits, to_bits}`
`uXX` -> `iXX` via `cast_unsigned` and `cast_signed`
{`char` -> `u32`, `bool` -> `n8`} via `from`
`u32` -> `char` via `from_u32_unchecked` (note: notes `from_u32().unwrap()`) (contested)
`u8` -> `bool` via `==` (debatable)

---
try-job: aarch64-gnu
try-job: test-various
2025-04-24 17:19:42 +02:00
bendn
c8c074288a
Suggest {to,from}_ne_bytes for transmutations between arrays and integers, etc 2025-04-24 13:14:36 +07:00
Matthias Krüger
32b2428c8b
Rollup merge of #139809 - alexcrichton:wasm-simd-safe, r=RalfJung
Don't warn about `v128` in wasm ABI transition

The `-Zwasm-c-abi=spec` mode of `extern "C"` does not actually change the meaning of `v128`  meaning that the FCW lint firing is a false positive.

cc https://github.com/rust-lang/rust/issues/138762#issuecomment-2801709483
2025-04-24 08:12:58 +02:00
Alex Crichton
19e44d463b Don't warn about v128 in wasm ABI transition
This has other warnings if necessary and doesn't need extra warnings
from this FCW.

cc #138762
2025-04-22 15:11:23 -07:00
bors
8bf5a8d12f Auto merge of #132833 - est31:stabilize_let_chains, r=fee1-dead
Stabilize let chains in the 2024 edition

# Stabilization report

This proposes the stabilization of `let_chains` ([tracking issue], [RFC 2497]) in the [2024 edition] of Rust.

[tracking issue]: https://github.com/rust-lang/rust/issues/53667
[RFC 2497]: https://github.com/rust-lang/rfcs/pull/2497
[2024 edition]: https://doc.rust-lang.org/nightly/edition-guide/rust-2024/index.html

## What is being stabilized

The ability to `&&`-chain `let` statements inside `if` and `while` is being stabilized, allowing intermixture with boolean expressions. The patterns inside the `let` sub-expressions can be irrefutable or refutable.

```Rust
struct FnCall<'a> {
    fn_name: &'a str,
    args: Vec<i32>,
}

fn is_legal_ident(s: &str) -> bool {
    s.chars()
        .all(|c| ('a'..='z').contains(&c) || ('A'..='Z').contains(&c))
}

impl<'a> FnCall<'a> {
    fn parse(s: &'a str) -> Option<Self> {
        if let Some((fn_name, after_name)) = s.split_once("(")
            && !fn_name.is_empty()
            && is_legal_ident(fn_name)
            && let Some((args_str, "")) = after_name.rsplit_once(")")
        {
            let args = args_str
                .split(',')
                .map(|arg| arg.parse())
                .collect::<Result<Vec<_>, _>>();
            args.ok().map(|args| FnCall { fn_name, args })
        } else {
            None
        }
    }
    fn exec(&self) -> Option<i32> {
        let iter = self.args.iter().copied();
        match self.fn_name {
            "sum" => Some(iter.sum()),
            "max" => iter.max(),
            "min" => iter.min(),
            _ => None,
        }
    }
}

fn main() {
    println!("{:?}", FnCall::parse("sum(1,2,3)").unwrap().exec());
    println!("{:?}", FnCall::parse("max(4,5)").unwrap().exec());
}
```

The feature will only be stabilized for the 2024 edition and future editions. Users of past editions will get an error with a hint to update the edition.

closes #53667

## Why 2024 edition?

Rust generally tries to ship new features to all editions. So even the oldest editions receive the newest features. However, sometimes a feature requires a breaking change so much that offering the feature without the breaking change makes no sense. This occurs rarely, but has happened in the 2018 edition already with `async` and `await` syntax. It required an edition boundary in order for `async`/`await` to become keywords, and the entire feature foots on those keywords.

In the instance of let chains, the issue is the drop order of `if let` chains. If we want `if let` chains to be compatible with `if let`, drop order makes it hard for us to [generate correct MIR]. It would be strange to have different behaviour for `if let ... {}` and `if true && let ... {}`. So it's better to [stay consistent with `if let`].

In edition 2024, [drop order changes] have been introduced to make `if let` temporaries be lived more shortly. These changes also affected `if let` chains. These changes make sense even if you don't take the `if let` chains MIR generation problem into account. But if we want to use them as the solution to the MIR generation problem, we need to restrict let chains to edition 2024 and beyond: for let chains, it's not just a change towards more sensible behaviour, but one required for correct function.

[generate correct MIR]: https://github.com/rust-lang/rust/issues/104843
[stay consistent with `if let`]: https://github.com/rust-lang/rust/pull/103293#issuecomment-1293408574
[drop order changes]: https://github.com/rust-lang/rust/issues/124085

## Introduction considerations

As edition 2024 is very new, this stabilization PR only makes it possible to use let chains on 2024 without that feature gate, it doesn't mark that feature gate as stable/removed. I would propose to continue offering the `let_chains` feature (behind a feature gate) for a limited time (maybe 3 months after stabilization?) on older editions to allow nightly users to adopt edition 2024 at their own pace. After that, the feature gate shall be marked as *stabilized*, not removed, and replaced by an error on editions 2021 and below.

## Implementation history

* History from before March 14, 2022 can be found in the [original stabilization PR] that was reverted.
* https://github.com/rust-lang/rust/pull/94927
* https://github.com/rust-lang/rust/pull/94951
* https://github.com/rust-lang/rust/pull/94974
* https://github.com/rust-lang/rust/pull/95008
* https://github.com/rust-lang/rust/pull/97295
* https://github.com/rust-lang/rust/pull/98633
* https://github.com/rust-lang/rust/pull/99731
* https://github.com/rust-lang/rust/pull/102394
* https://github.com/rust-lang/rust/pull/100526
* https://github.com/rust-lang/rust/pull/100538
* https://github.com/rust-lang/rust/pull/102998
* https://github.com/rust-lang/rust/pull/103405
* https://github.com/rust-lang/rust/pull/103293
* https://github.com/rust-lang/rust/pull/107251
* https://github.com/rust-lang/rust/pull/110568
* https://github.com/rust-lang/rust/pull/115677
* https://github.com/rust-lang/rust/pull/117743
* https://github.com/rust-lang/rust/pull/117770
* https://github.com/rust-lang/rust/pull/118191
* https://github.com/rust-lang/rust/pull/119554
* https://github.com/rust-lang/rust/pull/129394
* https://github.com/rust-lang/rust/pull/132828
* https://github.com/rust-lang/reference/pull/1179
* https://github.com/rust-lang/reference/pull/1251
* https://github.com/rust-lang/rustfmt/pull/5910

[original stabilization PR]: https://github.com/rust-lang/rust/pull/94927

## Adoption history

### In the compiler

* History before March 14, 2022 can be found in the [original stabilization PR].
* https://github.com/rust-lang/rust/pull/115983
* https://github.com/rust-lang/rust/pull/116549
* https://github.com/rust-lang/rust/pull/116688

### Outside of the compiler

* https://github.com/rust-lang/rust-clippy/pull/11750
* [rspack](https://github.com/web-infra-dev/rspack)
* [risingwave](https://github.com/risingwavelabs/risingwave)
* [dylint](https://github.com/trailofbits/dylint)
* [convex-backend](https://github.com/get-convex/convex-backend)
* [tikv](https://github.com/tikv/tikv)
* [Daft](https://github.com/Eventual-Inc/Daft)
* [greptimedb](https://github.com/GreptimeTeam/greptimedb)

## Tests

<details>

### Intentional restrictions

[`partially-macro-expanded.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/partially-macro-expanded.rs), [`macro-expanded.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/macro-expanded.rs): it is possible to use macros to expand to both the pattern and the expression inside a let chain, but not to the entire `let pat = expr` operand.
[`parens.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/parens.rs): `if (let pat = expr)` is not allowed in chains
[`ensure-that-let-else-does-not-interact-with-let-chains.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs): `let...else` doesn't support chaining.

### Overlap with match guards

[`move-guard-if-let-chain.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.rs): test for the `use moved value` error working well in match guards. could maybe be extended with let chains that have more than one `let`
[`shadowing.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/shadowing.rs): shadowing in if let guards works as expected
[`ast-validate-guards.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-validate-guards.rs): let chains in match guards require the match guards feature gate

### Simple cases from the early days

PR #88642 has added some tests with very simple usages of `let else`, mostly as regression tests to early bugs.

[`then-else-blocks.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/then-else-blocks.rs)
[`ast-lowering-does-not-wrap-let-chains.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs)
[`issue-90722.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-90722.rs)
[`issue-92145.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-92145.rs)

### Drop order/MIR scoping tests

[`issue-100276.rs`](4adafcf40a/tests/ui/drop/issue-100276.rs): let expressions on RHS aren't terminating scopes
[`drop_order.rs`](4adafcf40a/tests/ui/drop/drop_order.rs): exhaustive temporary drop order test for various Rust constructs, including let chains
[`scope.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/scope.rs): match guard scoping test
[`drop-scope.rs`](4adafcf40a/tests/ui/rfcs/rfc-2294-if-let-guard/drop-scope.rs): another match guard scoping test, ensuring that temporaries in if-let guards live for the arm
[`drop_order_if_let_rescope.rs`](4adafcf40a/tests/ui/drop/drop_order_if_let_rescope.rs): if let rescoping on edition 2024, including chains
[`mir_let_chains_drop_order.rs`](4adafcf40a/tests/ui/mir/mir_let_chains_drop_order.rs): comprehensive drop order test for let chains, distinguishes editions 2021 and 2024.
[`issue-99938.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/issue-99938.rs), [`issue-99852.rs`](4adafcf40a/tests/ui/mir/issue-99852.rs) both bad MIR ICEs fixed by #102394

### Linting

[`irrefutable-lets.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/irrefutable-lets.rs): trailing and leading irrefutable let patterns get linted for, others don't. The lint is turned off for `else if`.
[`issue-121070-let-range.rs`](4adafcf40a/tests/ui/lint/issue-121070-let-range.rs): regression test for false positive of the unused parens lint, precedence requires the `()`s here

### Parser: intentional restrictions

[`disallowed-positions.rs`](2128d8df0e/tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs): `let` in expression context is rejected everywhere except at the top level
[`invalid-let-in-a-valid-let-context.rs`](4adafcf40a/tests/ui/rfcs/rfc-2497-if-let-chains/invalid-let-in-a-valid-let-context.rs): nested `let` is not allowed (let's are no legal expressions just because they are allowed in `if` and `while`).

### Parser: recovery

[`issue-103381.rs`](4adafcf40a/tests/ui/parser/issues/issue-103381.rs): Graceful recovery of incorrect chaining of `if` and `if let`
[`semi-in-let-chain.rs`](4adafcf40a/tests/ui/parser/semi-in-let-chain.rs): Ensure that stray `;`s in let chains give nice errors (`if_chain!` users might be accustomed to `;`s)
[`deli-ident-issue-1.rs`](4adafcf40a/tests/ui/parser/deli-ident-issue-1.rs), [`brace-in-let-chain.rs`](4adafcf40a/tests/ui/parser/brace-in-let-chain.rs): Ensure that stray unclosed `{`s in let chains give nice errors and hints

### Misc

[`conflicting_bindings.rs`](4adafcf40a/tests/ui/pattern/usefulness/conflicting_bindings.rs): the conflicting bindings check also works in let chains. Personally, I'd extend it to chains with multiple let's as well.
[`let-chains-attr.rs`](4adafcf40a/tests/ui/expr/if/attrs/let-chains-attr.rs): attributes work on let chains

### Tangential tests with `#![feature(let_chains)]`

[`if-let.rs`](4adafcf40a/tests/coverage/branch/if-let.rs): MC/DC coverage tests for let chains
[`logical_or_in_conditional.rs`](4adafcf40a/tests/mir-opt/building/logical_or_in_conditional.rs): not really about let chains, more about dropping/scoping behaviour of `||`
[`stringify.rs`](4adafcf40a/tests/ui/macros/stringify.rs): exhaustive test of the `stringify` macro
[`expanded-interpolation.rs`](4adafcf40a/tests/ui/unpretty/expanded-interpolation.rs), [`expanded-exhaustive.rs`](4adafcf40a/tests/ui/unpretty/expanded-exhaustive.rs): Exhaustive test of `-Zunpretty`
[`diverges-not.rs`](4adafcf40a/tests/ui/rfcs/rfc-0000-never_patterns/diverges-not.rs): Never type, mostly tangential to let chains

</details>

## Possible future work

* There is proposals to allow `if let Pat(bindings) = expr {}` to be written as `if expr is Pat(bindings) {}` ([RFC 3573]). `if let` chains are a natural extension of the already existing `if let` syntax, and I'd argue orthogonal towards `is` syntax.
  * https://github.com/rust-lang/lang-team/issues/297
* One could have similar chaining inside `let ... else` statements. There is no proposed RFC for this however, nor is it implemented on nightly.
* Match guards have the `if` keyword as well, but on stable Rust, they don't support `let`. The functionality is available via an unstable feature ([`if_let_guard` tracking issue]). Stabilization of let chains affects this feature in so far as match guards containing let chains now only need the `if_let_guard` feature gate be present instead of also the `let_chains` feature (NOTE: this PR doesn't implement this simplification, it's left for future work).

[RFC 3573]: https://github.com/rust-lang/rfcs/pull/3573
[`if_let_guard` tracking issue]: https://github.com/rust-lang/rust/issues/51114

## Open questions / blockers

- [ ] bad recovery if you don't put a `let` (I don't think this is a blocker): [#117977](https://github.com/rust-lang/rust/issues/117977)
- [x] An instance where a temporary lives shorter than with nested ifs, breaking compilation: [#103476](https://github.com/rust-lang/rust/issues/103476). Personally I don't think this is a blocker either, as it's an edge case. Edit: turns out to not reproduce in edition 2025 any more, due to let rescoping. regression test added in #133093
- [x] One should probably extend the tests for `move-guard-if-let-chain.rs` and `conflicting_bindings.rs` to have chains with multiple let's: done in 133093
- [x] Parsing rejection tests: addressed by https://github.com/rust-lang/rust/pull/132828
- [x] [Style](https://rust-lang.zulipchat.com/#narrow/channel/346005-t-style/topic/let.20chains.20stabilization.20and.20formatting): https://github.com/rust-lang/rust/pull/139456
- [x] https://github.com/rust-lang/rust/issues/86730 explicitly mentions `let_else`. I think we can live with `let pat = expr` not evaluating as `expr` for macro_rules macros, especially given that `let pat = expr` is not a legal expression anywhere except inside `if` and `while`.
- [x] Documentation in the reference: https://github.com/rust-lang/reference/pull/1740
- [x] Add chapter to the Rust 2024 [edition guide]: https://github.com/rust-lang/edition-guide/pull/337
- [x] Resolve open questions on desired drop order.

[original reference PR]: https://github.com/rust-lang/reference/pull/1179
[edition guide]: https://github.com/rust-lang/edition-guide
2025-04-22 07:54:10 +00:00
Urgau
8307f97253 Check bare function idents for non snake-case name 2025-04-20 19:24:23 +02:00
Urgau
40ba47d3b0 Implement lint against dangerous implicit autorefs 2025-04-20 11:36:28 +02:00