1
Fork 0
Commit graph

45949 commits

Author SHA1 Message Date
Stuart Cook
ae745a06fa
Rollup merge of #138950 - yaahc:svh-metrics-name, r=bjorn3
replace extra_filename with strict version hash in metrics file names

Should resolve the potential issue of overwriting metrics from the same crate when compiled with different features or flags.

r? `````@estebank`````

try-job: test-various
2025-04-05 13:18:15 +11:00
Stuart Cook
93f7583491
Rollup merge of #138826 - makai410:assoc-items, r=celinval
StableMIR: Add `associated_items`.

Resolves: https://github.com/rust-lang/project-stable-mir/issues/87
2025-04-05 13:18:15 +11:00
Stuart Cook
c6bf3a01ef
Rollup merge of #137880 - EnzymeAD:autodiff-batching, r=oli-obk
Autodiff batching

Enzyme supports batching, which is especially known from the ML side when training neural networks.
There we would normally have a training loop, where in each iteration we would pass in some data (e.g. an image), and a target vector. Based on how close we are with our prediction we compute our loss, and then use backpropagation to compute the gradients and update our weights.
That's quite inefficient, so what you normally do is passing in a batch of 8/16/.. images and targets, and compute the gradients for those all at once, allowing better optimizations.

Enzyme supports batching in two ways, the first one (which I implemented here) just accepts a Batch size,
and then each Dual/Duplicated argument has not one, but N shadow arguments.  So instead of
```rs
for i in 0..100 {
   df(x[i], y[i], 1234);
}
```
You can now do
```rs
for i in 0..100.step_by(4) {
   df(x[i+0],x[i+1],x[i+2],x[i+3], y[i+0], y[i+1], y[i+2], y[i+3], 1234);
}
```
which will give the same results, but allows better compiler optimizations. See the testcase for details.

There is a second variant, where we can mark certain arguments and instead of having to pass in N shadow arguments, Enzyme assumes that the argument is N times longer. I.e. instead of accepting 4 slices with 12 floats each, we would accept one slice with 48 floats. I'll implement this over the next days.

I will also add more tests for both modes.

For any one preferring some more interactive explanation, here's a video of Tim's llvm dev talk, where he presents his work. https://www.youtube.com/watch?v=edvaLAL5RqU
I'll also add some other docs to the dev guide and user docs in another PR.

r? ghost

Tracking:

- https://github.com/rust-lang/rust/issues/124509
- https://github.com/rust-lang/rust/issues/135283
2025-04-05 13:18:13 +11:00
bors
bad13a970a Auto merge of #139390 - matthiaskrgr:rollup-l64euwx, r=matthiaskrgr
Rollup of 9 pull requests

Successful merges:

 - #139041 (Remove `rustc_middle::ty::util::ExplicitSelf`.)
 - #139328 (Fix 2024 edition doctest panic output)
 - #139339 (unstable book: document tait)
 - #139348 (AsyncDestructor: replace fields with impl_did)
 - #139353 (Fix `Debug` impl for `LateParamRegionKind`.)
 - #139366 (ToSocketAddrs: fix typo)
 - #139374 (Use the span of the whole bound when the diagnostic talks about a bound)
 - #139378 (Use target-agnostic LLD flags in bootstrap for `use-lld`)
 - #139384 (Add `compiletest` adhoc_group for `r? compiletest`)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-04-04 23:03:57 +00:00
Michael Goulet
6dfbe7c986 Detect and provide suggestion for &raw EXPR 2025-04-04 21:36:12 +00:00
Michael Goulet
f343b9d1fd Don't construct preds w escaping bound vars in diagnostic_hir_wf_check 2025-04-04 21:09:32 +00:00
Takayuki Maeda
6b5ccfc87f check if merged attributes list is empty 2025-04-05 06:09:14 +09:00
Guillaume Gomez
2e3a161871 Update rustc-literal-escaper version to 0.0.2 2025-04-04 22:26:10 +02:00
Matthias Krüger
f074bbff7a
Rollup merge of #139374 - oli-obk:const-trait-bound, r=compiler-errors
Use the span of the whole bound when the diagnostic talks about a bound

While it makes sense that the host predicate only points to the `~const` part, as whether the actual trait bound is satisfied is checked separately, the user facing diagnostic is talking about the entire trait bound, at which point it makes more sense to just highlight the entire bound

r? `@compiler-errors` or `@fee1-dead`
2025-04-04 21:55:00 +02:00
Matthias Krüger
fa7d66eaaa
Rollup merge of #139366 - RalfJung:ToSocketAddrs, r=jieyouxu
ToSocketAddrs: fix typo

It's "a function", never "an function".

I noticed the same typo somewhere in the compiler sources so figured I'd fix it there as well.
2025-04-04 21:54:59 +02:00
Matthias Krüger
e3c73c7a2f
Rollup merge of #139353 - nnethercote:LateAnon, r=compiler-errors
Fix `Debug` impl for `LateParamRegionKind`.

It uses `Br` prefixes which are inappropriate and appear to have been incorrectly copy/pasted from the `Debug` impl for `BoundRegionKind`.

r? `@BoxyUwU`
2025-04-04 21:54:58 +02:00
Matthias Krüger
d61a4735f7
Rollup merge of #139348 - meithecatte:async-destructor-minify, r=petrochenkov
AsyncDestructor: replace fields with impl_did

The future and ctor fields aren't actually used, and the way they are extracted is obviously wrong – swapping the order of the items in the source code will give wrong results.

Instead, store just the LocalDefId of the impl, which is enough for the only use of this data.
2025-04-04 21:54:58 +02:00
Matthias Krüger
00f608af18
Rollup merge of #139041 - nnethercote:rm-rustc_middle-ty-util-ExplicitSelf, r=BoxyUwU
Remove `rustc_middle::ty::util::ExplicitSelf`.

It's an old (2017 or earlier) type that describes a `self` receiver. It's only used in `rustc_hir_analysis` for two error messages, and much of the complexity isn't used. I suspect it used to be used for more things.

This commit removes it, and moves a greatly simplified version of the `determine` method into `rustc_hir_analysis`, renamed as `get_self_string`. The big comment on the method is removed because it no longer seems relevant.

r? `@BoxyUwU`
2025-04-04 21:54:56 +02:00
bors
17ffbc81a3 Auto merge of #138785 - lcnr:typing-mode-borrowck, r=compiler-errors,oli-obk
add `TypingMode::Borrowck`

Shares the first commit with #138499, doesn't really matter which PR to land first 😊 😁

Introduces `TypingMode::Borrowck` which unlike `TypingMode::Analysis`, uses the hidden type computed by HIR typeck as the initial value of opaques instead of an unconstrained infer var. This is a part of https://github.com/rust-lang/types-team/issues/129.

Using this new `TypingMode` is unfortunately a breaking change for now, see tests/ui/impl-trait/non-defining-uses/as-projection-term.rs. Using an inference variable as the initial value results in non-defining uses in the defining scope. We therefore only enable it if with `-Znext-solver=globally` or `-Ztyping-mode-borrowck`

To do that the PR contains the following changes:
- `TypeckResults::concrete_opaque_type` are already mapped to the definition of the opaque type
  - writeback now checks that the non-lifetime parameters of the opaque are universal
  - for this, `fn check_opaque_type_parameter_valid` is moved from `rustc_borrowck` to `rustc_trait_selection`
- we add a new `query type_of_opaque_hir_typeck` which, using the same visitors as MIR typeck, attempts to merge the hidden types from HIR typeck from all defining scopes
  - done by adding a `DefiningScopeKind` flag to toggle between using borrowck and HIR typeck
  - the visitors stop checking that the MIR type matches the HIR type. This is trivial as the HIR type are now used as the initial hidden types of the opaque. This check is useful as a safeguard when not using `TypingMode::Borrowck`, but adding it to the new structure is annoying and it's not soundness critical, so I intend to not add it back.
- add a `TypingMode::Borrowck`  which behaves just like `TypingMode::Analysis` except when normalizing opaque types
   - it uses `type_of_opaque_hir_typeck(opaque)` as the initial value after replacing its regions with new inference vars
   - it uses structural lookup in the new solver

fixes #112201, fixes #132335, fixes #137751

r? `@compiler-errors` `@oli-obk`
2025-04-04 19:54:42 +00:00
Manuel Drehwald
89d8948835 add new flag to print the module post-AD, before opts 2025-04-04 14:25:23 -04:00
Manuel Drehwald
b7c63a973f add autodiff batching backend 2025-04-04 14:24:23 -04:00
bors
5337252b99 Auto merge of #137869 - Noratrieb:Now_I_am_become_death,_the_destroyer_of_i686-pc-windows-gnu, r=workingjubilee
Demote i686-pc-windows-gnu to Tier 2

In accordance with [RFC 3771](https://github.com/rust-lang/rfcs/pull/3771). FCP has been completed.

tracking issue #138422

I also added a stub doc page for the target and renamed the windows-gnullvm page for consistency.
2025-04-04 15:45:03 +00:00
Oli Scherer
a69a219f96 Use the span of the whole bound when the diagnostic talks about a bound 2025-04-04 13:39:50 +00:00
Mads Marquart
7e4379c4eb refactor: Move env parsing of deployment target to rustc_session 2025-04-04 15:02:22 +02:00
Mads Marquart
d74ce25b65 refactor: Move Apple OSVersion (back) to rustc_target
Also convert OSVersion into a proper struct for better type-safety.
2025-04-04 15:01:27 +02:00
Ralf Jung
0f12a2c4ad ToSocketAddrs: fix typo 2025-04-04 14:47:04 +02:00
Guillaume Gomez
aff2bc7a88 Replace rustc_lexer/unescape with rustc-literal-escaper crate 2025-04-04 14:44:45 +02:00
Camille GILLOT
280a1d8edb Do not visit whole crate to compute lints_that_dont_need_to_run. 2025-04-04 12:37:38 +00:00
Bryanskiy
0522ed059d Default auto traits: fix perf 2025-04-04 15:32:00 +03:00
bors
b8ff7b682e Auto merge of #139213 - bjorn3:cg_clif_test_coretests, r=jieyouxu
Run coretests and alloctests with cg_clif in CI

Part of https://github.com/rust-lang/rustc_codegen_cranelift/issues/1290
2025-04-04 11:59:59 +00:00
morine0122
d0591827dd Make the compiler suggest actual paths instead of visible paths if the visible paths are through any doc hidden path. 2025-04-04 20:50:16 +09:00
Camille GILLOT
d9caf840e1 Only introduce stable projections. 2025-04-04 10:55:42 +00:00
Camille GILLOT
109edab245 Allow GVN to produce places and not just locals. 2025-04-04 10:55:36 +00:00
Mara Bos
6c3417dd15 fixup! Implement super let. 2025-04-04 11:16:32 +02:00
bors
a4166dabaa Auto merge of #139354 - matthiaskrgr:rollup-04lgx23, r=matthiaskrgr
Rollup of 8 pull requests

Successful merges:

 - #138949 (Rename `is_like_osx` to `is_like_darwin`)
 - #139295 (Remove creation of duplicate `AnonPipe`)
 - #139313 (Deduplicate some `rustc_middle` function bodies by calling the `rustc_type_ir` equivalent)
 - #139317 (compiletest: Encapsulate all of the code that touches libtest)
 - #139322 (Add helper function for checking LLD usage to `run-make-support`)
 - #139335 (Pass correct param-env to `error_implies`)
 - #139342 (Add a mailmap entry for myself)
 - #139349 (adt_destructor: sanity-check returned item)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-04-04 08:52:02 +00:00
Mara Bos
3e6cc7689d Boolean hate. 2025-04-04 09:44:22 +02:00
Mara Bos
f02e278639 Fix typo in pretty printing super let.
Co-authored-by: lcnr <rust@lcnr.de>
2025-04-04 09:44:22 +02:00
Mara Bos
3123df8ef0 Implement super let. 2025-04-04 09:44:19 +02:00
Matthias Krüger
0a9eae161b
Rollup merge of #139349 - meithecatte:destructor-constness, r=compiler-errors
adt_destructor: sanity-check returned item

Fixes #139278
2025-04-04 08:02:09 +02:00
Matthias Krüger
c264f3e4d8
Rollup merge of #139335 - compiler-errors:error-implies, r=oli-obk
Pass correct param-env to `error_implies`

Duplicated comment from the test:

In the error reporting code, when reporting fulfillment errors for goals A and B, we try to see if elaborating A will result in another goal that can equate with B. That would signal that B is "implied by" A, allowing us to skip reporting it, which is beneficial for cutting down on the number of diagnostics we report.

In the new trait solver especially, but even in the old trait solver through things like defining opaque type usages, this `can_equate` call was not properly taking the param-env of the goals, resulting in nested obligations that had empty param-envs. If one of these nested obligations was a `ConstParamHasTy` goal, then we would ICE, since those goals are particularly strict about the param-env they're evaluated in.

This is morally a fix for <https://github.com/rust-lang/rust/issues/139314>, but that repro uses details about how defining usages in the `check_opaque_well_formed` code can spring out of type equality, and will likely stop failing soon coincidentally once we start using `PostBorrowck` mode in that check. Instead, we use lazy normalization to end up generating an alias-eq goal whose nested goals woul trigger the ICE instead, since this is a lot more stable.

Fixes https://github.com/rust-lang/rust/issues/139314

r? ``@oli-obk`` or reassign
2025-04-04 08:02:08 +02:00
Matthias Krüger
96ab10c087
Rollup merge of #139313 - oli-obk:push-uzvmpxqyvrzp, r=compiler-errors
Deduplicate some `rustc_middle` function bodies by calling the `rustc_type_ir` equivalent

Maybe in the future we can use method delegation, but I'd rather avoid that for now (I don't even know if it can do that already)
2025-04-04 08:02:06 +02:00
Matthias Krüger
66e61c78e7
Rollup merge of #138949 - madsmtm:rename-to-darwin, r=WaffleLapkin
Rename `is_like_osx` to `is_like_darwin`

Replace `is_like_osx` with `is_like_darwin`, which more closely describes reality (OS X is the pre-2016 name for macOS, and is by now quite outdated; Darwin is the overall name for the OS underlying Apple's macOS, iOS, etc.).

``@rustbot`` label O-apple
r? compiler
2025-04-04 08:02:05 +02:00
Nicholas Nethercote
fadf910517 Fix Debug impl for LateParamRegionKind.
It uses `Br` prefixes which are inappropriate and appear to have been
incorrectly copy/pasted from the `Debug` impl for `BoundRegionKind`.
2025-04-04 16:50:56 +11:00
bors
f174fd716a Auto merge of #139287 - compiler-errors:folder-experiment-1, r=lqd
Folder experiment: Monomorphize region resolver

**NOTE:** This is one of a series of perf experiments that I've come up with while sick in bed. I'm assigning them to lqd b/c you're a good reviewer and you'll hopefully be awake when these experiments finish, lol.

r? lqd

This is actually two tweaks to the `RegionFolder`, monomorphizing its callback and accounting for flags to avoid folding unnecessarily.
2025-04-04 05:41:45 +00:00
Maja Kądziołka
a14e8f687c
adt_destructor: sanity-check returned item
Fixes #139278
2025-04-04 05:18:48 +02:00
Maja Kądziołka
a2618e1af0
AsyncDestructor: replace fields with impl_did
The future and ctor fields aren't actually used, and the way they are
extracted is obviously wrong – swapping the order of the items in the
source code will give wrong results.

Instead, store just the LocalDefId of the impl, which is enough for the
only use of this data.
2025-04-04 05:04:58 +02:00
Nicholas Nethercote
b9e13cb539 Apply Recovery::Forbidden when reparsing pasted macro fragments.
Fixes #137874.

Removes `tests/crashes/137874.rs`; the new test is simpler (defines its
own macro) but tests the same thing.

The changes to the output of `tests/ui/associated-consts/issue-93835.rs`
partly undo the changes seen when `NtTy` was removed in #133436, which
is good.
2025-04-04 13:24:26 +11:00
bors
9e14530c7c Auto merge of #120706 - Bryanskiy:leak, r=lcnr
Initial support for auto traits with default bounds

This PR is part of ["MCP: Low level components for async drop"](https://github.com/rust-lang/compiler-team/issues/727)
Tracking issue: #138781
Summary: https://github.com/rust-lang/rust/pull/120706#issuecomment-1934006762

### Intro

Sometimes we want to use type system to express specific behavior and provide safety guarantees. This behavior can be specified by various "marker" traits. For example, we use `Send` and `Sync` to keep track of which types are thread safe. As the language develops, there are more problems that could be solved by adding new marker traits:

- to forbid types with an async destructor to be dropped in a synchronous context a trait like `SyncDrop` could be used [Async destructors, async genericity and completion futures](https://sabrinajewson.org/blog/async-drop).
- to support [scoped tasks](https://without.boats/blog/the-scoped-task-trilemma/) or in a more general sense to provide a [destruction guarantee](https://zetanumbers.github.io/book/myosotis.html) there is a desire among some users to see a `Leak` (or `Forget`) trait.
- Withoutboats in his [post](https://without.boats/blog/changing-the-rules-of-rust/) reflected on the use of `Move` trait instead of a `Pin`.

All the traits proposed above are supposed to be auto traits implemented for most types, and usually implemented automatically by compiler.

For backward compatibility these traits have to be added implicitly to all bound lists in old code (see below). Adding new default bounds involves many difficulties: many standard library interfaces may need to opt out of those default bounds, and therefore be infected with confusing `?Trait` syntax, migration to a new edition may contain backward compatibility holes, supporting new traits in the compiler can be quite difficult and so forth. Anyway, it's hard to evaluate the complexity until we try the system on a practice.

In this PR we introduce new optional lang items for traits that are added to all bound lists by default, similarly to existing `Sized`. The examples of such traits could be `Leak`, `Move`, `SyncDrop` or something else, it doesn't matter much right now (further I will call them `DefaultAutoTrait`'s). We want to land this change into rustc under an option, so it becomes available in bootstrap compiler. Then we'll be able to do standard library experiments with the aforementioned traits without adding hundreds of `#[cfg(not(bootstrap))]`s. Based on the experiments, we can come up with some scheme for the next edition, in which such bounds are added in a more targeted way, and not just everywhere.

Most of the implementation is basically a refactoring that replaces hardcoded uses of `Sized` with iterating over a list of traits including both `Sized` and the new traits when `-Zexperimental-default-bounds` is enabled (or just `Sized` as before, if the option is not enabled).

### Default bounds for old editions

All existing types, including generic parameters, are considered `Leak`/`Move`/`SyncDrop` and can be forgotten, moved or destroyed in generic contexts without specifying any bounds. New types that cannot be, for example, forgotten and do not implement `Leak` can be added at some point, and they should not be usable in such generic contexts in existing code.

To both maintain this property and keep backward compatibility with existing code, the new traits should be added as default bounds _everywhere_ in previous editions. Besides the implicit `Sized` bound contexts that includes supertrait lists and trait lists in trait objects (`dyn Trait1 + ... + TraitN`). Compiler should also generate implicit `DefaultAutoTrait` implementations for foreign types (`extern { type Foo; }`) because they are also currently usable in generic contexts without any bounds.

#### Supertraits

Adding the new traits as supertraits to all existing traits is potentially necessary, because, for example, using a `Self` param in a trait's associated item may be a breaking change otherwise:

```rust
trait Foo: Sized {
    fn new() -> Option<Self>; // ERROR: `Option` requires `DefaultAutoTrait`, but `Self` is not `DefaultAutoTrait`
}

// desugared `Option`
enum Option<T: DefaultAutoTrait + Sized> {
    Some(T),
    None,
}
```

However, default supertraits can significantly affect compiler performance. For example, if we know that `T: Trait`, the compiler would deduce that `T: DefaultAutoTrait`. It also implies proving `F: DefaultAutoTrait` for each field `F` of type `T` until an explicit impl is be provided.

If the standard library is not modified, then even traits like `Copy` or `Send` would get these supertraits.

In this PR for optimization purposes instead of adding default supertraits, bounds are added to the associated items:

```rust
// Default bounds are generated in the following way:
trait Trait {
   fn foo(&self) where Self: DefaultAutoTrait {}
}

// instead of this:
trait Trait: DefaultAutoTrait {
   fn foo(&self) {}
}
```

It is not always possible to do this optimization because of backward compatibility:

```rust
pub trait Trait<Rhs = Self> {}
pub trait Trait1 : Trait {} // ERROR: `Rhs` requires `DefaultAutoTrait`, but `Self` is not `DefaultAutoTrait`
```

or

```rust
trait Trait {
   type Type where Self: Sized;
}
trait Trait2<T> : Trait<Type = T> {} // ERROR: `???` requires `DefaultAutoTrait`, but `Self` is not `DefaultAutoTrait`
```

Therefore, `DefaultAutoTrait`'s are still being added to supertraits if the `Self` params or type bindings were found in the trait header.

#### Trait objects

Trait objects requires explicit `+ Trait` bound to implement corresponding trait which is not backward compatible:

```rust
fn use_trait_object(x: Box<dyn Trait>) {
   foo(x) // ERROR: `foo` requires `DefaultAutoTrait`, but `dyn Trait` is not `DefaultAutoTrait`
}

// implicit T: DefaultAutoTrait here
fn foo<T>(_: T) {}
```

So, for a trait object `dyn Trait` we should add an implicit bound `dyn Trait + DefaultAutoTrait` to make it usable, and allow relaxing it with a question mark syntax `dyn Trait + ?DefaultAutoTrait` when it's not necessary.

#### Foreign types

If compiler doesn't generate auto trait implementations for a foreign type, then it's a breaking change if the default bounds are added everywhere else:

```rust
// implicit T: DefaultAutoTrait here
fn foo<T: ?Sized>(_: &T) {}

extern "C" {
    type ExternTy;
}

fn forward_extern_ty(x: &ExternTy) {
    foo(x); // ERROR: `foo` requires `DefaultAutoTrait`, but `ExternTy` is not `DefaultAutoTrait`
}
```

We'll have to enable implicit `DefaultAutoTrait` implementations for foreign types at least for previous editions:

```rust
// implicit T: DefaultAutoTrait here
fn foo<T: ?Sized>(_: &T) {}

extern "C" {
    type ExternTy;
}

impl DefaultAutoTrait for ExternTy {} // implicit impl

fn forward_extern_ty(x: &ExternTy) {
    foo(x); // OK
}
```

### Unresolved questions

New default bounds affect all existing Rust code complicating an already complex type system.

- Proving an auto trait predicate requires recursively traversing the type and proving the predicate for it's fields. This leads to a significant performance regression. Measurements for the stage 2 compiler build show up to 3x regression.
    - We hope that fast path optimizations for well known traits could mitigate such regressions at least partially.
- New default bounds trigger some compiler bugs in both old and new trait solver.
- With new default bounds we encounter some trait solver cycle errors that break existing code.
    - We hope that these cases are bugs that can be addressed in the new trait solver.

Also migration to a new edition could be quite ugly and enormous, but that's actually what we want to solve. For other issues there's a chance that they could be solved by a new solver.
2025-04-04 01:35:52 +00:00
Nicholas Nethercote
aa1b7bf070 Remove an unwanted comment.
I accidentally added this in #138740.
2025-04-04 09:59:25 +11:00
bors
4fd8c04da0 Auto merge of #139336 - matthiaskrgr:rollup-zsi8pgf, r=matthiaskrgr
Rollup of 9 pull requests

Successful merges:

 - #138017 (Tighten up assignment operator representations.)
 - #138462 (Dedup `&mut *` reborrow suggestion in loops)
 - #138610 (impl !PartialOrd for HirId)
 - #138767 (Allow boolean literals in `check-cfg`)
 - #139068 (io: Avoid marking some bytes as uninit)
 - #139255 (Remove unused variables generated in merged doctests)
 - #139270 (Add a mailmap entry for myself)
 - #139303 (Put Noratrieb on vacation)
 - #139312 (add Marco Ieni to mailmap)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-04-03 22:26:29 +00:00
Manuel Drehwald
e0c8ead880 add autodiff batching middle-end 2025-04-03 17:21:21 -04:00
Manuel Drehwald
087ffd73bf add the autodiff batch mode frontend 2025-04-03 17:19:11 -04:00
Matthias Krüger
9d733eca06
Rollup merge of #138767 - clubby789:check-cfg-bool, r=Urgau
Allow boolean literals in `check-cfg`

https://github.com/rust-lang/rust/pull/138632#issuecomment-2738114495
This makes it consistent with `--cfg`

We could alternatively add a forward-compatible lint against `--cfg true/false`
r? `@Urgau`
2025-04-03 21:18:30 +02:00
Matthias Krüger
48a3919884
Rollup merge of #138610 - oli-obk:no-sort-hir-ids, r=compiler-errors
impl !PartialOrd for HirId

revive of https://github.com/rust-lang/rust/pull/92233

Another checkbox of https://github.com/rust-lang/rust/issues/90317, another small step in making incremental less likely to die in horrible ways
2025-04-03 21:18:30 +02:00
Matthias Krüger
731ce84d19
Rollup merge of #138462 - ShE3py:mut-borrow-in-loop, r=oli-obk
Dedup `&mut *` reborrow suggestion in loops

#73534 added a reborrow suggestion in loops; #127579 generalized this to generic parameters, making the suggestion triggers twice:
```rs
use std::io::Read;

fn decode_scalar(_reader: impl Read) {}
fn decode_array(reader: &mut impl Read) {
    for _ in 0.. {
        decode_scalar(reader);
    }
}
```
```
error[E0382]: use of moved value: `reader`
 --> src/lib.rs:6:23
  |
4 | fn decode_array(reader: &mut impl Read) {
  |                 ------ move occurs because `reader` has type `&mut impl Read`, which does not implement the `Copy` trait
5 |     for _ in 0.. {
  |     ------------ inside of this loop
6 |         decode_scalar(reader);
  |                       ^^^^^^ value moved here, in previous iteration of loop
  |
help: consider creating a fresh reborrow of `reader` here
  |
6 |         decode_scalar(&mut *reader);
  |                       ++++++
help: consider creating a fresh reborrow of `reader` here
  |
6 |         decode_scalar(&mut *reader);
  |                       ++++++
```
This PR removes the suggestion in loops, as it requires generic parameters anyway (i.e., the reborrow is automatic if there is no generic params).

`@rustbot` label +A-borrow-checker +A-diagnostics +A-suggestion-diagnostics +D-papercut
2025-04-03 21:18:29 +02:00