Jump threading stores values as `u128` (`ScalarInt`) and does its
comparisons for equality as integer comparisons.
This works great for integers. Sadly, not everything is an integer.
Floats famously have wonky equality semantcs, with `NaN!=NaN` and
`0.0 == -0.0`. This does not match our beautiful integer bitpattern
equality and therefore causes things to go horribly wrong.
While jump threading could be extended to support floats by remembering
that they're floats in the value state and handling them properly,
it's signficantly easier to just disable it for now.
Make `missing_fragment_specifier` an error in edition 2024
`missing_fragment_specifier` has been a future compatibility warning since 2017. Uplifting it to an unconditional hard error was attempted in 2020, but eventually reverted due to fallout.
Make it an error only in edition >= 2024, leaving the lint for older editions. This change will make it easier to support more macro syntax that relies on usage of `$`.
Fixes <https://github.com/rust-lang/rust/issues/40107>
---
It is rather late for the edition but since this change is relatively small, it seems worth at least bringing up. This follows a brief [Zulip discussion](https://rust-lang.zulipchat.com/#narrow/stream/268952-edition/topic/.60.20DBD.20-.3E.20hard.20error) (cc `@tmandry).`
Making this an edition-dependent lint has come up before but there was not a strong motivation. I am proposing it at this time because this would simplify the [named macro capture groups](https://github.com/rust-lang/rfcs/pull/3649) RFC, which has had mildly positive response, and makes use of new `$` syntax in the matcher. The proposed syntax currently parses as metavariables without a fragment specifier; this warning is raised, but there are no errors.
It is obviously not known that this specific RFC will eventually be accepted, but forbidding `missing_fragment_specifier` should make it easier to support any new syntax in the future that makes use of `$` in different ways. The syntax conflict is also not impossible to overcome, but making it clear that unnamed metavariables are rejected makes things more straightforward and should allow for better diagnostics.
`@Mark-Simulacrum` suggested making this forbid-by-default instead of an error at https://github.com/rust-lang/rust/issues/40107#issuecomment-761727885, but I don't think this would allow the same level of syntax flexibility.
It is also possible to reconsider making this an unconditional error since four years have elapsed since the previous attempt, but this seems likely to hit the same pitfalls. (Possibly worth a crater run?)
Tracking:
- https://github.com/rust-lang/rust/issues/128143
- merge error codes
- use attribute name that is incompatible in error message
- add test for conditional incompatible attribute
- add `linkage` to the allowlist
`missing_fragment_specifier` has been a future compatibility warning
since 2017. Uplifting it to an unconditional hard error was attempted in
2020, but eventually reverted due to fallout.
Make it an error only in edition >= 2024, leaving the lint for older
editions. This change will make it easier to support more macro syntax
that relies on usage of `$`.
Fixes <https://github.com/rust-lang/rust/issues/40107>
Improve `extern "<abi>" unsafe fn()` error message
These errors were already reported in #87217, and fixed by #87235 but missed the case of an explicit ABI.
This PR does not cover multiple keywords like `extern "C" pub const unsafe fn()`, but I don't know what a good way to cover this would be. It also seems rarer than `extern "C" unsafe` which I saw happen a few times in workshops.
Implement `Copy`/`Clone` for async closures
We can do so in the same cases that regular closures do.
For the purposes of cloning, coroutine-closures are actually precisely the same as regular closures, specifically in the aspect that `Clone` impls care about which is the upvars. The only difference b/w coroutine-closures and regular closures is the type that they *return*, but this type has not been *created* yet, so we don't really have a problem.
IDK why I didn't add this impl initially -- I went back and forth a bit on the internal representation for coroutine-closures before settling on a design which largely models regular closures. Previous (not published) iterations of coroutine-closures used to be represented as a special (read: cursed) kind of coroutine, which would probably suffer from the pitfalls that coroutines have that oli mentioned below in https://github.com/rust-lang/rust/pull/128201#issuecomment-2251230274.
r? oli-obk
Stabilize const `{integer}::from_str_radix` i.e. `const_int_from_str`
This PR stabilizes the feature `const_int_from_str`.
- ACP Issue: rust-lang/libs-team#74
- Implementation PR: rust-lang/rust#99322
- Part of Tracking Issue: rust-lang/rust#59133
API Change Diff:
```diff
impl {integer} {
- pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
+ pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
}
impl ParseIntError {
- pub fn kind(&self) -> &IntErrorKind;
+ pub const fn kind(&self) -> &IntErrorKind;
}
```
This makes it easier to parse integers at compile-time, e.g.
the example from the Tracking Issue:
```rust
env!("SOMETHING").parse::<usize>().unwrap()
```
could now be achived with
```rust
match usize::from_str_radix(env!("SOMETHING"), 10) {
Ok(val) => val,
Err(err) => panic!("Invalid value for SOMETHING environment variable."),
}
```
rather than having to depend on a library that implements or manually implement the parsing at compile-time.
---
Checklist based on [Libs Stabilization Guide - When there's const involved](https://std-dev-guide.rust-lang.org/development/stabilization.html#when-theres-const-involved)
I am treating this as a [partial stabilization](https://std-dev-guide.rust-lang.org/development/stabilization.html#partial-stabilizations) as it shares a tracking issue (and is rather small), so directly opening the partial stabilization PR for the subset (feature `const_int_from_str`) being stabilized.
- [x] ping Constant Evaluation WG
- [x] no unsafe involved
- [x] no `#[allow_internal_unstable]`
- [ ] usage of `intrinsic::const_eval_select` rust-lang/rust#124625 in `from_str_radix_assert` to change the error message between compile-time and run-time
- [ ] [rust-labg/libs-api FCP](https://github.com/rust-lang/rust/pull/124941#issuecomment-2207021921)
Support ?Trait bounds in supertraits and dyn Trait under a feature gate
This patch allows `maybe` polarity bounds under a feature gate. The only language change here is that corresponding hard errors are replaced by feature gates. Example:
```rust
#![feature(allow_maybe_polarity)]
...
trait Trait1 : ?Trait { ... } // ok
fn foo(_: Box<(dyn Trait2 + ?Trait)>) {} // ok
fn bar<T: ?Sized + ?Trait>(_: &T) {} // ok
```
Maybe bounds still don't do anything (except for `Sized` trait), however this patch will allow us to [experiment with default auto traits](https://github.com/rust-lang/rust/pull/120706#issuecomment-1934006762).
This is a part of the [MCP: Low level components for async drop](https://github.com/rust-lang/compiler-team/issues/727)
Migrate `c-unwind-abi-catch-lib-panic`, `foreign-rust-exceptions` and `export-executable-symbols` `run-make` tests to rmake
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
Please try:
try-job: aarch64-apple
try-job: i686-mingw
Let InstCombine remove Clone shims inside Clone shims
The Clone shims that we generate tend to recurse into other Clone shims, which gets very silly very quickly. Here's our current state: https://godbolt.org/z/E69YeY8eq
So I've added InstSimplify to the shims optimization passes, and improved `is_trivially_pure_clone_copy` so that it can delete those calls inside the shim. This makes the shim way smaller because most of its size is the required ceremony for unwinding.
This change also completely breaks the UI test added for https://github.com/rust-lang/rust/issues/104870. With this PR, that program ICEs in MIR type checking because `is_trivially_pure_clone_copy` and the trait solver disagree on whether `*mut u8` is `Copy`. And adding the requisite `Copy` impl to make them agree makes the test not generate any diagnostics. Considering that I spent most of my time on this PR fixing `#![no_core]` tests, I would prefer to just delete this one. The maintenance burden of `#![no_core]` is uniquely high because when they break they tend to break in very confusing ways.
try-job: x86_64-mingw
exhaustiveness: Explain why a given pattern is considered unreachable
This PR tells the user why a given pattern is considered unreachable. I reused the intersection information we were already computing; even though it's incomplete I convinced myself that it is sufficient to always get a set of patterns that cover the unreachable one.
I'm not a fan of the diagnostic messages I came up with, I'm open to suggestions.
Fixes https://github.com/rust-lang/rust/issues/127870. This is also the other one of the two diagnostic improvements I wanted to do before https://github.com/rust-lang/rust/pull/122792.
Note: the first commit is an unrelated drive-by tweak.
r? `@compiler-errors`
Migrate `interdependent-c-libraries`, `compiler-rt-works-on-mingw` and `incr-foreign-head-span` `run-make` tests to rmake
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
try-job: aarch64-apple
try-job: armhf-gnu
try-job: test-various
try-job: x86_64-mingw
try-job: x86_64-msvc
try-job: x86_64-gnu-llvm-18
Extend rules of dead code analysis for impls for adts to impls for types refer to adts
The rules of dead code analysis for impl blocks can be extended to self types which refer to adts.
So that we can lint the following unused struct and trait:
```rust
struct Foo; //~ ERROR struct `Foo` is never constructed
trait Trait { //~ ERROR trait `Trait` is never used
fn foo(&self) {}
}
impl Trait for &Foo {}
```
r? `@pnkfelix`
Make it crystal clear what lint `type_alias_bounds` actually signifies
This is part of my work on https://github.com/rust-lang/rust/labels/F-lazy_type_alias ([tracking issue](#112792)).
---
To recap, the lint `type_alias_bounds` detects bounds on generic parameters and where clauses on (eager) type aliases. These bounds should've never been allowed because they are currently neither enforced[^1] at usage sites of type aliases nor thoroughly checked for correctness at definition sites due to the way type aliases are represented in the compiler. Allowing them was an oversight.
Explicitly label this as a known limitation of the type checker/system and establish the experimental feature `lazy_type_alias` as its eventual proper solution.
Where this becomes a bit tricky (for me as a rustc dev) are the "secondary effects" of these bounds whose existence I sadly can't deny. As a matter of fact, type alias bounds do play some small roles during type checking. However, after a lot of thinking over the last two weeks I've come to the conclusion (not without second-guessing myself though) that these use cases should not trump the fact that these bounds are currently *inherently broken*. Therefore the lint `type_alias_bounds` should and will continue to flag bounds that may have subordinate uses.
The two *known* secondary effects are:
1. They may enable the use of "shorthand" associated type paths `T::Assoc` (as opposed to fully qualified paths `<T as Trait>::Assoc`) where `T` is a type param bounded by some trait `Trait` which defines that assoc ty.
2. They may affect the default lifetime of trait object types passed as a type argument to the type alias. That concept is called (trait) object lifetime default.
The second one is negligible, no question asked. The first one however is actually "kinda nice" (for writability) and comes up in practice from time to time.
So why don't I just special-case trait bounds that "define" shorthand assoc type paths as originally planned in #125709?
1. Starting to permit even a tiny subset of bounds would already be enough to send a signal to users that bounds in type aliases have been legitimized and that they can expect to see type alias bounds in the wild from now on (proliferation). This would be actively misleading and dangerous because those bounds don't behave at all like one would expect, they are *not real*[^2]!
1. Let's take `type A<T: Trait> = T::Proj;` for example. Everywhere else in the language `T: Trait` means `T: Trait + Sized`. For type aliases, that's not the case though: `T: Trait` and `T: Trait + ?Sized` for that matter do neither mean `T: Trait + Sized` nor `T: Trait + ?Sized` (for both!). Instead, whether `T` requires `Sized` or not entirely depends on the definition of `Trait`[^2]. Namely, whether or not it is bounded by `Sized`.
2. Given `type A<T: Trait<AssocA = ()>> = T::AssocB;`, while `X: Trait` gets checked given `A<X>` (by virtue of projection wfchecking post alias expansion[^2]), the associated type constraint `AssocA = ()` gets dropped entirely! While we could choose to warn on such cases, it would inevitably lead to a huge pile of special cases.
3. While it's common knowledge that the body / aliased type / RHS of an (eager) type alias does not get checked for well-formedness, I'm not sure if people would realize that that extends to bounds as well. Namely, `type A<T: Trait<[u8]>> = T::Proj;` compiles even if `Trait`'s generic parameter requires `Sized`. Of course, at usage sites `[u8]: Sized` would still end up getting checked[^2], so it's not a huge problem if you have full control over `A`. However, imagine that `A` was actually part of a public API and was never used inside the defining crate (not unreasonable). In such a scenario, downstream users would be presented with an impossible to use type alias! Remember, bounds may grow arbitrarily complex and nuanced in practice.
4. Even if we allowed trait bounds that "define" shorthand assoc type paths, we would still need to continue to warn in cases where the assoc ty comes from a supertrait despite the fact that the shorthand syntax can be used: `type A<T: Sub> = T::Assoc;` does compile given `trait Sub: Super {}` and `trait Super { type Assoc; }`. However, `A<X>` does not enforce `X: Sub`, only `X: Super`[^2]. All that to say, type alias bounds are simply not real and we shouldn't pretend they are!
5. Summarizing the points above, we would be legitimizing bounds that are completely broken!
2. It's infeasible to implement: Due to the lack of `TypeckResults` in `ItemCtxt` (and a way to propagate it to other parts of the compiler), the resolution of type-dependent paths in non-`Body` items (most notably type aliases) is not recoverable from the HIR alone which would be necessary because the information of whether an associated type path (projection) is a shorthand is only present pre&in-HIR and doesn't survive HIR ty lowering. Of course, I could rerun parts of HIR ty lowering inside the lint `type_alias_bounds` (namely, `probe_single_ty_param_bound_for_assoc_ty` which would need to be exposed or alternatively a stripped-down version of it). This likely has a performance impact and introduces complexity. In short, the "benefits" are not worth the costs.
---
* 3rd commit: Update a diagnostic to avoid suggesting type alias bounds
* 4th commit: Flag type alias bounds even if the RHS contains inherent associated types.
* I started to allow them at some point in the past which was not correct (see commit for details)
* 5th commit: Allow type alias bounds if the RHS contains const projections and GCEs are enabled
* (and add a `FIXME(generic_const_exprs)` to be revisited before (M)GCE's stabilization)
* As a matter of fact type alias bounds are enforced in this case because the contained AnonConsts do get checked for well-formedness and crucially they inherit the generics and predicates of their parent item (here: the type alias)
* Remaining commits: Improve the lint `type_alias_bounds` itself
---
Fixes#125789 (sugg diag fix).
Fixes#125709 (wontfix, acknowledgement, sugg diag applic fix).
Fixes#104918 (sugg diag applic fix).
Fixes#100270 (wontfix, acknowledgement, sugg diag applic fix).
Fixes#94398 (true fix).
r? `@compiler-errors` `@oli-obk`
[^1]: From the perspective of the trait solver.
[^2]: Given `type A<T: Trait> = T::Proj;`, the reason why the trait bound "`T: Trait`" gets *seemingly* enforced at usage sites of the type alias `A` is simply because `A<X>` gets expanded to "`<X as Trait>::Proj`" very early on and it's the *expansion* that gets checked for well-formedness, not the type alias reference.
Graciously handle `Drop` impls introducing more generic parameters than the ADT
Follow up to #110577Fixes#126378Fixes#126889
## Motivation
A current issue with the way we check drop impls do not specialize any of their generic parameters is that when the `Drop` impl introduces *more* generic parameters than are present on the ADT, we fail to prove any bounds involving those parameters. This can be demonstrated with the following [code on stable](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=139b65e4294634d7286a3282bc61e628) which fails due to the fact that `<T as Trait>::Assoc == U` is not present in `Foo`s `ParamEnv` even though arguably there is no reason it cannot compiler:
```rust
struct Foo<T: Trait>(T);
trait Trait {
type Assoc;
}
impl<T: Trait<Assoc = U>, U: ?Sized> Drop for Foo<T> {
//~^ ERROR: `Drop` impl requires `<T as Trait>::Assoc == U` but the struct ...
fn drop(&mut self) {}
}
fn main() {}
```
I think the motivation for supporting this code is somewhat lacking, it might be useful in practice for deeply nested associated types where you might want to be able to write:
`where T: Trait<Assoc: Other<AnotherAssoc: MoreTrait<YetAnotherAssoc: InnerTrait<Final = U>>>>`
in order to be able to just use `U` in the function body instead of writing out the whole nested associated type. Regardless I don't think there is really any reason to *not* support this code and it is relatively easy to support it.
What I find slightly more compelling is the fact that when defining a const parameter `const N: u8` we desugar that to having a where clause requiring the constant `N` is typed as `u8` (`ClauseKind::ConstArgHasType`). As we *always* desugar const parameters to have these bounds, if we attempt to prove that some const parameter `N` is of type `u8` and there is no bound on `N` in the enviroment that generally indicates usage of an incorrect `ParamEnv` (this has caught a bug already).
Given that, if we write the following code:
```rust
#![feature(associated_const_equality)]
struct Foo<T: Trait>(T);
trait Trait {
const ASSOC: usize;
}
impl<T: Trait<ASSOC = N>, const N: usize> Drop for Foo<T> {
fn drop(&mut self) {}
}
fn main() {}
```
The `Drop` impl would have this desugared where clause about `N` being of type `usize`, and if we were to try to prove that where clause in `Foo`'s `ParamEnv` we would ICE as there would not be any `ConstArgHasType` in the environment (which generally indicates improper `ParamEnv` usage. As this is otherwise well formed code (the `T: Trait<ASSOC = N>` causes `N` to be constrained) we have to handle this *somehow* and I believe the only principled way to support this is the changes I have made to `dropck.rs` that would cause these code examples to compiler (Perhaps we could just throw out all `ConstArgHasType` where clauses from the predicates we prove but that makes me nervous even if it might actually be okay).
## The changes
Currently the way `dropck.rs` works is that take the `ParamEnv` of the ADT and instantiate it with the generic arguments used on the self ty of the `impl`. We then instantiate the predicates of the drop impl with the identity params to the impl, e.g. in the original example `<T as Trait>::Assoc == U` stays as `<T as Trait>::Assoc == U`. We then attempt to prove all the where clauses in the instantiated env of the self type ADT.
This PR changes us to first instantiate the impl with infer vars, then we equate the self type (with infer vars as its generic arguments) with the self type as written by the user. This causes all generic parameters on the impl that are constrained via associated type/const equality bounds to be left as inference variables while all other parameters are still `Ty`/`Const`/`Region`
Finally when instantiating the predicates on the impl, instead of using the identity arguments, we use the list of inference variables of which some have been inferred to the impl parameters. In practice this means that we wind up proving `<T as Trait>::Assoc == ?x` which can succeed just fine. In the const generics example we would wind up trying to prove `ConstArgHasType(?x: usize)` instead of `ConstArgHasType(N: usize)` which avoids the ICE as it is expected to encounter goals of the form `?x: usize`.
At a higher level the way I justify/think about this is that as we are proving goals in the environment of the ADT (`Foo` in the above examples), we do not expect to encounter generic parameters from a different environment so we must "deal with them" somehow. In this PR we handle them by replacing them with inference variables as they should either *actually* be unconstrained (and we will error later) or they are constrained to be equal to some associated type/const.
To go along with this it would be nice if we were not instantiating the adt's env with the generic arguments to the ADT in the `Drop` impl as it would make it clearer we are proving bounds in the adt's env instead of the `Drop` impl's. Instead we would map the predicates on the drop impl to be valid in the environment of the adt. In practice this causes diagnostic regressions as all of the generic parameters in errors refer to the ones defined on the adt; attempting to map these back to the ones on the impl, while possible, is involved as writing a `TypeFolder` over `FulfillmentError` is non trivial.
## Edge cases
There are some subtle interactions here:
One is that we should not allow `<T as Trait>::Assoc == U` to be present on the `Drop` if `U` is constrained by the self type of the impl and the bound is not present in the ADT's environment. demonstrated with the [following code](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=af839e2c3e43e03a624825c58af84dff):
```rust
trait Trait {
type Assoc;
}
struct Foo<T: Trait, U: ?Sized>(T, U);
impl<T: Trait<Assoc = U>, U: ?Sized> Drop for Foo<T, U> {
//~^ ERROR: `Drop` impl requires `<T as Trait>::Assoc == U`
fn drop(&mut self) {}
}
fn main() {}
```
This is tested at `tests/ui/dropck/constrained_by_assoc_type_equality_and_self_ty.rs`.
Another weirdness is that we permit the following code to compile now:
```rust
struct Foo<T>(T);
impl<'a, T: 'a> Drop for Foo<T> {
fn drop(&mut self) {}
}
```
This is caused by the fact that we permit unconstrained lifetime parameters in trait implementations as long as they are not used in associated types (so we do not wind up erroring on this code like we perhaps ought to), combined with the fact that as we are now proving `T: '?x` instead of `T: 'a` which allows proving the bound via `'?x= 'empty` wheras previously it would have failed.
This is tested as part of `tests/ui/dropck/reject-specialized-drops-8142.rs`.
---
r? `@compiler-errors`
Fix supertrait associated type unsoundness
### What?
Object safety allows us to name `Self::Assoc` associated types in certain positions if they come from our trait or one of our supertraits. When this check was implemented, I think it failed to consider that supertraits can have different args, and it was only checking def-id equality.
This is problematic, since we can sneak different implementations in by implementing `Supertrait<NotActuallyTheSupertraitSubsts>` for a `dyn` type. This can be used to implement an unsound transmute function. See the committed test.
### How do we fix it?
We consider the whole trait ref when checking for supertraits. Right now, this is implemented using equality *without* normalization. We erase regions since those don't affect trait selection.
This is a limitation that could theoretically affect code that should be accepted, but doesn't matter in practice -- there are 0 crater regression. We could make this check stronger, but I would be worried about cycle issues. I assume that most people are writing `Self::Assoc` so they don't really care about the trait ref being normalized.
---
### What is up w the stacked commit
This is built on top of https://github.com/rust-lang/rust/pull/122804 though that's really not related, it's just easier to make this modification with the changes to the object safety code that I did in that PR. The only thing is that PR may make this unsoundness slightly easier to abuse, since there are more positions that allow self-associated-types -- I am happy to stall that change until this PR merges.
---
Fixes#126079
r? lcnr
Switch from `derivative` to `derive-where`
This is a part of the effort to get rid of `syn 1.*` in compiler's dependencies: #109302
Derivative has not been maintained in nearly 3 years[^1]. It also depends on `syn 1.*`.
This PR replaces `derivative` with `derive-where`[^2], a not dead alternative, which uses `syn 2.*`.
A couple of `Debug` formats have changed around the skipped fields[^3], but I doubt this is an issue.
[^1]: https://github.com/mcarton/rust-derivative/issues/117
[^2]: https://lib.rs/crates/derive-where
[^3]: See the changes in `tests/ui`
Add basic Serde serialization capabilities to Stable MIR
This PR adds basic Serde serialization capabilities to Stable MIR. It is intentionally minimal (just wrapping all stable MIR types with a Serde `derive`), so that any important design decisions can be discussed before going further. A simple test is included with this PR to validate that JSON can actually be emitted.
## Notes
When I wrapped the Stable MIR error types in `compiler/stable_mir/src/error.rs`, it caused test failures (though I'm not sure why) so I backed those out.
## Future Work
So, this PR will support serializing basic stable MIR, but it _does not_ support serializing interned values beneath `Ty`s and `AllocId`s, etc... My current thinking about how to handle this is as follows:
1. Add new `visited_X` fields to the `Tables` struct for each interned category of interest.
2. As serialization is occuring, serialize interned values as usual _and_ also record the interned value we referenced in `visited_X`.
(Possibly) In addition, if an interned value recursively references other interned values, record those interned values as well.
3. Teach the stable MIR `Context` how to access the `visited_X` values and expose them with wrappers in `stable_mir/src/lib.rs` to users (e.g. to serialize and/or further analyze them).
### Pros
This approach does not commit to any specific serialization format regarding interned values or other more complex cases, which avoids us locking into any behaviors that may not be desired long-term.
### Cons
The user will need to manually handle serializing interned values.
### Alternatives
1. We can directly provide access to the underlying `Tables` maps for interned values; the disadvantage of this approach is that it either requires extra processing for users to filter out to only use the values that they need _or_ users may serialize extra values that they don't need. The advantage is that the implementation is even simpler. The other pros/cons are similar to the above.
2. We can directly serialize interned values by expanding them in-place. The pro is that this may make some basic inputs easier to consume. However, the cons are that there will need to be special provisions for dealing with cyclical values on both the producer and consumer _and_ global values will possibly need to be de-duplicated on the consumer side.
Rollup of 6 pull requests
Successful merges:
- #126908 (Use Cow<'static, str> for InlineAsmTemplatePiece::String)
- #127999 (Inject arm32 shims into Windows metadata generation)
- #128137 (CStr: derive PartialEq, Eq; add test for Ord)
- #128185 (Fix a span error when parsing a wrong param of function.)
- #128187 (Fix 1.80.0 version in RELEASES.md)
- #128189 (Turn an unreachable code path into an ICE)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix a span error when parsing a wrong param of function.
fixes#128042
Before this change, the span of param `*mut Self` in `fn oof(*mut Self)` contains `(` before it, so the suggestion in E0424 will be error.
Remove crashes for misuses of intrinsics
All of these do not crash if the feature gate is removed. An ICE due *opting into* the intrinsics feature gate is not a bug that needs to be fixed, but instead a misuse of an internal-only API.
See https://github.com/rust-lang/compiler-team/issues/620
The last two issues are already closed anyways, but:
Fixes#97501Fixes#111699Fixes#101962
Don't ICE if HIR and middle types disagree in borrowck error reporting
We try to match up the `middle::ty::Ty` and `hir::Ty` types in borrowck error reporting, but due to things like `Self` self type alias, or regular type aliases, these might not match up. Don't ICE.
This PR also tries to recover the error by looking up the self type of the impl in case we see `Self`. The diagnostic is frankly quite confusing, but I also didn't really want to look at it because I don't understand the conflict error reporting logic. 🤷Fixes#121816
Make sure that args are compatible in `resolve_associated_item`
Implements a similar check to the one that we have in projection for GATs (#102488, #123240), where we check that the args of an impl item are compatible before returning it. This is done in `resolve_assoc_item`, which is backing `Instance::resolve`, so this is conceptually generalizing the check from GATs to methods/assoc consts. This is important to make sure that the inliner will only visit and substitute MIR bodies that are compatible w/ their trait definitions.
This shouldn't happen in codegen, but there are a few ways to get the inliner to be invoked (via calls to `optimized_mir`) before codegen, namely polymorphization and CTFE.
Fixes#121957Fixes#120792Fixes#120793Fixes#121063
`#[naked]`: use an allowlist for allowed options on `asm!` in naked functions
tracking issue: https://github.com/rust-lang/rust/issues/90957
this is mostly just a refactor, but using an allowlist (rather than a denylist) for which asm options are allowed in naked functions is a little safer.
These options are disallowed because naked functions are effectively global asm, but defined using inline asm.
Implement lint against ambiguous negative literals
This PR implements a lint against ambiguous negative literals with a literal and method calls right after it.
## `ambiguous_negative_literals`
(deny-by-default)
The `ambiguous_negative_literals` lint checks for cases that are confusing between a negative literal and a negation that's not part of the literal.
### Example
```rust,compile_fail
-1i32.abs(); // equals -1, while `(-1i32).abs()` equals 1
```
### Explanation
Method calls take precedence over unary precedence. Setting the precedence explicitly makes the code clearer and avoid potential bugs.
<details>
<summary>Old proposed lint</summary>
## `ambiguous_unary_precedence`
(deny-by-default)
The `ambiguous_unary_precedence` lint checks for use the negative unary operator with a literal and method calls.
### Example
```rust
-1i32.abs(); // equals -1, while `(-1i32).abs()` equals 1
```
### Explanation
Unary operations take precedence on binary operations and method calls take precedence over unary precedence. Setting the precedence explicitly makes the code clearer and avoid potential bugs.
</details>
-----
Note: This is a strip down version of https://github.com/rust-lang/rust/pull/117161, without the binary op precedence.
Fixes https://github.com/rust-lang/rust/issues/117155
`@rustbot` labels +I-lang-nominated
cc `@scottmcm`
r? compiler
Don't ICE when auto trait has assoc ty in old solver
Kinda a pointless change to make, but it's observable w/o the feature gate, so let's just fix it. I reintroduced this ICE when I removed the "auto impl" kind from `ImplSource` in #112687.
Fixes#117829Fixes#127746
Do not use question as label
We don't want to have questions in the diagnostic output. Instead, we use wording that communicates uncertainty, like "might":
```
error[E0432]: unresolved import `spam`
--> $DIR/import-from-missing-star-3.rs:2:9
|
LL | use spam::*;
| ^^^^ you might be missing crate `spam`
|
= help: consider adding `extern crate spam` to use the `spam` crate
```
Migrate `pointer-auth-link-with-c`, `c-dynamic-rlib` and `c-dynamic-dylib` `run-make` tests to rmake
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
Please try:
try-job: x86_64-msvc
try-job: i686-mingw
try-job: aarch64-apple
Replace ASCII control chars with Unicode Control Pictures
Replace ASCII control chars like `CR` with Unicode Control Pictures like `␍`:
```
error: bare CR not allowed in doc-comment
--> $DIR/lex-bare-cr-string-literal-doc-comment.rs:3:32
|
LL | /// doc comment with bare CR: '␍'
| ^
```
Centralize the checking of unicode char width for the purposes of CLI display in one place. Account for the new replacements. Remove unneeded tracking of "zero-width" unicode chars, as we calculate these in the `SourceMap` as needed now.
Reorder trait bound modifiers *after* `for<...>` binder in trait bounds
This PR suggests changing the grammar of trait bounds from:
```
[CONSTNESS] [ASYNCNESS] [?] [BINDER] [TRAIT_PATH]
const async ? for<'a> Sized
```
to
```
([BINDER] [CONSTNESS] [ASYNCNESS] | [?]) [TRAIT_PATH]
```
i.e., either
```
? Sized
```
or
```
for<'a> const async Sized
```
(but not both)
### Why?
I think it's strange that the binder applies "more tightly" than the `?` trait polarity. This becomes even weirder when considering that we (or at least, I) want to have `async` trait bounds expressed like:
```
where T: for<'a> async Fn(&'a ()) -> i32,
```
and not:
```
where T: async for<'a> Fn(&'a ()) -> i32,
```
### Fallout
No crates on crater use this syntax, presumably because it's literally useless. This will require modifying the reference grammar, though.
### Alternatives
If this is not desirable, then we can alternatively keep parsing `for<'a>` after the `?` but deprecate it with either an FCW (or an immediate hard error), and begin parsing `for<'a>` *before* the `?`.
We don't want to have questions in the diagnostic output. Instead, we use wording that communicates uncertainty, like "might":
```
error[E0432]: unresolved import `spam`
--> $DIR/import-from-missing-star-3.rs:2:9
|
LL | use spam::*;
| ^^^^ you might be missing crate `spam`
|
= help: consider adding `extern crate spam` to use the `spam` crate
```
Mark `missing_fragment_specifier` as `FutureReleaseErrorReportInDeps`
We are moving toward forbidding `missing_fragment_specifier` either in edition 2024 or unconditionally. Make a first step toward this by ensuring crates that rely on the old behavior are reported when used as dependencies.
Tracking issue: <https://github.com/rust-lang/rust/issues/128143>
Fix malformed suggestion for repeated maybe unsized bounds
Fixes#127441
Now when we encounter something like `foo(a : impl ?Sized + ?Sized)`, instead of suggesting removal of both bounds and leaving `foo(a: impl )` behind, we suggest changing the first bound to `Sized` and removing the second bound, resulting in `foo(a: impl Sized)`.
Although the issue was reported for impl trait types, it also occurred with regular param bounds. So if we encounter `foo<T: ?Sized + ?Sized>(a: T)` we now detect that all the bounds are `?Sized` and therefore emit the suggestion to remove the entire predicate `: ?Sized + ?Sized` resulting in `foo<T>(a: T)`.
Lastly, if we encounter a situation where some of the bounds are something other than `?Sized`, then we emit separate removal suggestions for each `?Sized` bound. E.g. if we see `foo(a: impl ?Sized + Bar + ?Sized)` or `foo<T: ?Sized + Bar + ?Sized>(a: T)` we emit suggestions such that the user will be left with `foo(a : impl Bar)` or `foo<T: Bar>(a: T)` respectively.
Do not try to reveal hidden types when trying to prove auto-traits in the defining scope
fixes#99793
this avoids the cycle error by just causing a selection error, which is not fatal. We pessimistically assume that freeze does not hold, which is always a safe assumption.
We are moving toward forbidding `missing_fragment_specifier` either in
edition 2024 or unconditionally. Make a first step toward this by
ensuring crates that rely on the old behavior are reported when used as
dependencies.
Tracking issue: <https://github.com/rust-lang/rust/issues/128143>
Improve spans on evaluated `cfg_attr`s.
When converting something like `#![cfg_attr(cond, attr)]` into `#![attr]`, we currently duplicate the `#` token and the `!` token. But weirdly, there is also this comment:
// We don't really have a good span to use for the synthesized `[]`
// in `#[attr]`, so just use the span of the `#` token.
Maybe that comment used to be true? But now it is false: we can duplicate the existing delimiters (and their spans and spacing), much like we do for the `#` and `!`.
This commit does that, thus removing the incorrect comment, and improving the spans on `Group`s in a few proc-macro tests.
`@petrochenkov`
Gate `AsyncFn*` under `async_closure` feature
T-lang has not come to a consensus on the naming of async closure callable bounds, and as part of allowing the async closures RFC merge, we agreed to place `AsyncFn` under the same gate as `async Fn` so that these syntaxes can be evaluated in parallel.
See https://github.com/rust-lang/rfcs/pull/3668#issuecomment-2246435537
r? oli-obk
Since LLVM 19, it is necessary to set not only module flags, but
also function attributes for branch protection on aarch64. See
e15d67cfc2
for the relevant LLVM change.
Do not use global caches if opaque types can be defined
fixes#119272
r? `@lcnr`
This is certainly a crude way to make the cache sound wrt opaque types, but since perf lets us get away with this, let's do it in the old solver and let the new solver fix this correctly once and for all.
cc https://github.com/rust-lang/rust/pull/122192#issuecomment-2149252655
When converting something like `#![cfg_attr(cond, attr)]` into
`#![attr]`, we currently duplicate the `#` token and the `!` token. But
weirdly, there is also this comment:
// We don't really have a good span to use for the synthesized `[]`
// in `#[attr]`, so just use the span of the `#` token.
Maybe that comment used to be true? But now it is false: we can
duplicate the existing delimiters (and their spans and spacing), much
like we do for the `#` and `!`.
This commit does that, thus removing the incorrect comment, and
improving the spans on `Group`s in a few proc-macro tests.
Make ast `MutVisitor` have the same method name and style as `Visitor`
It doesn't map 100% because some `MutVisitor` methods can filter or even expand to multiple items, but consistency seems nicer.
tracking issue: https://github.com/rust-lang/rust/issues/127615
Remove generic lifetime parameter of trait `Pattern`
Use a GAT for `Searcher` associated type because this trait is always implemented for every lifetime anyway.
cc #27721
Note closure captures when reporting cast to fn ptr failed
Fixes#128078
We already had logic to point out a closure having captures when that's possibly the source of a coercion error to `fn()`, but we weren't reporting it during an explicit `as` cast.
Migrate `lto-linkage-used-attr`, `no-duplicate-libs` and `pgo-gen-no-imp-symbols` `run-make` tests to rmake
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
try-job: x86_64-msvc
try-job: aarch64-apple
try-job: armhf-gnu
try-job: test-various
try-job: x86_64-gnu-llvm-18
