std: replace `LazyBox` with `OnceBox`
This PR replaces the `LazyBox` wrapper used to allocate the pthread primitives with `OnceBox`, which has a more familiar API mirroring that of `OnceLock`. This cleans up the code in preparation for larger changes like #128184 (from which this PR was split) and allows some neat optimizations, like avoid an acquire-load of the allocation pointer in `Mutex::unlock`, where the initialization of the allocation must have already been observed.
Additionally, I've gotten rid of the TEEOS `Condvar` code, it's just a duplicate of the pthread one anyway and I didn't want to repeat myself.
Prefer refutable slice patterns over len check + index op
Just something I noticed while reviewing other PRs
We do it for shim arguments almost everywhere, but when the size is not statically known, we didn't use the helpers as they rely on array ops. But we can avoid a len check followed by several index ops by just using a refutable slice pattern with `let else`.
The pattern is so common, it seems almost worth a dedicated macro
Make opaque types regular HIR nodes
Having opaque types as HIR owner introduces all sorts of complications. This PR proposes to make them regular HIR nodes instead.
I haven't gone through all the test changes yet, so there may be a few surprises.
Many thanks to `@camelid` for the first draft.
Fixes https://github.com/rust-lang/rust/issues/129023Fixes#129099Fixes#125843Fixes#119716Fixes#121422
Account for `impl Trait {` when `impl Trait for Type {` was intended
On editions where bare traits are never allowed, detect if the user has written `impl Trait` with no type, silence any dyn-compatibility errors, and provide a structured suggestion for the potentially missing type:
```
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/missing-for-type-in-impl.rs:8:6
|
LL | impl Foo<i64> {
| ^^^^^^^^
|
help: add `dyn` keyword before this trait
|
LL | impl dyn Foo<i64> {
| +++
help: you might have intended to implement this trait for a given type
|
LL | impl Foo<i64> for /* Type */ {
| ++++++++++++++
```
CC #131051.
Fix needless_lifetimes in stable_mir
Hi,
This PR fixes the following clippy warning in stable_mir
```
warning: the following explicit lifetimes could be elided: 'a
--> compiler/stable_mir/src/mir/visit.rs:79:30
|
79 | fn visit_projection_elem<'a>(
| ^^
80 | &mut self,
81 | place_ref: PlaceRef<'a>,
| ^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
= note: `#[warn(clippy::needless_lifetimes)]` on by default
help: elide the lifetimes
|
79 ~ fn visit_projection_elem(
80 | &mut self,
81 ~ place_ref: PlaceRef<'_>,
|
```
Best regards,
Michal
Add support for reborrowing pinned method receivers
This builds on #130526 to add pinned reborrowing for method receivers. This enables the folllowing examples to work:
```rust
#![feature(pin_ergonomics)]
#![allow(incomplete_features)]
use std::pin::Pin;
pub struct Foo;
impl Foo {
fn foo(self: Pin<&mut Self>) {
}
fn baz(self: Pin<&Self>) {
}
}
pub fn bar(x: Pin<&mut Foo>) {
x.foo();
x.foo();
x.baz(); // Pin<&mut Foo> is downgraded to Pin<&Foo>
}
pub fn baaz(x: Pin<&Foo>) {
x.baz();
x.baz();
}
```
This PR includes the original one, which is currently in the commit queue, but the only code changes are in the latest commit (d3c53aaa5c6fcb1018c58d229bc5d92202fa6880).
#130494
r? `@compiler-errors`
Check elaborated projections from dyn don't mention unconstrained late bound lifetimes
Check that the projections that are *not* explicitly written but which we deduce from elaborating the principal of a `dyn` *also* do not reference unconstrained late-bound lifetimes, just like the ones that the user writes by hand.
That is to say, given:
```
trait Foo<T>: Bar<Assoc = T> {}
trait Bar {
type Assoc;
}
```
The type `dyn for<'a> Foo<&'a T>` (basically) elaborates to `dyn for<'a> Foo<&'a T> + for<'a> Bar<Assoc = &'a T>`[^1]. However, the `Bar` projection predicate is not well-formed, since `'a` must show up in the trait's arguments to be referenced in the term of a projection. We must error in this situation[^well], or else `dyn for<'a> Foo<&'a T>` is unsound.
We already detect this for user-written projections during HIR->rustc_middle conversion, so this largely replicates that logic using the helper functions that were already conveniently defined.
---
I'm cratering this first to see the fallout; if it's minimal or zero, then let's land it as-is. If not, the way that this is implemented is very conducive to an FCW.
---
Fixes#130347
[^1]: We don't actually elaborate it like that in rustc; we only keep the principal trait ref `Foo<&'a T>` and the projection part of `Bar<Assoc = ...>`, but it's useful to be a bit verbose here for the purpose of explaining the issue.
[^well]: Well, we could also make `dyn for<'a> Foo<&'a T>` *not* implement `for<'a> Bar<Assoc = &'a T>`, but this is inconsistent with the case where the user writes `Assoc = ...` in the type itself, and it overly complicates the implementation of trait objects' built-in impls.
Update cargo
17 commits in 80d82ca22abbee5fb7b51fa1abeb1ae34e99e88a..ad074abe3a18ce8444c06f962ceecfd056acfc73
2024-09-27 17:56:01 +0000 to 2024-10-04 18:18:15 +0000
- test: Remove the last of our custom json assertions (rust-lang/cargo#14576)
- docs(ref): Expand on MSRV (rust-lang/cargo#14636)
- docs: Minor re-grouping of pages (rust-lang/cargo#14620)
- docs(ref): Highleft whats left for msrv-policy (rust-lang/cargo#14638)
- Fix `cargo:version_number` - has only one `:` (rust-lang/cargo#14637)
- docs: Declare support level for each crate in our Charter / docs (rust-lang/cargo#14600)
- chore(deps): update tar to 0.4.42 (rust-lang/cargo#14632)
- docs(charter): Declare new Intentional Artifacts as 'small' changes (rust-lang/cargo#14599)
- fix: Remove implicit feature removal (rust-lang/cargo#14630)
- docs(config): make `--config <PATH>` more prominent (rust-lang/cargo#14631)
- chore(deps): update rust crate unicode-width to 0.2.0 (rust-lang/cargo#14624)
- chore(deps): update embarkstudios/cargo-deny-action action to v2 (rust-lang/cargo#14628)
- docs(ref): Clean up language for `package.rust-version` (rust-lang/cargo#14619)
- docs: clarify `target.'cfg(...)'` doesnt respect cfg from build script (rust-lang/cargo#14312)
- test: relax compiler panic assertions (rust-lang/cargo#14618)
- refactor(compiler): zero-copy deserialization when possible (rust-lang/cargo#14608)
- test: add support for features in the sat resolver (rust-lang/cargo#14583)
On editions where bare traits are never allowed, detect if the user has
written `impl Trait` with no type, silence any dyn-compatibility errors,
and provide a structured suggestion for the potentially missing type:
```
error[E0782]: trait objects must include the `dyn` keyword
--> $DIR/missing-for-type-in-impl.rs:8:6
|
LL | impl Foo<i64> {
| ^^^^^^^^
|
help: add `dyn` keyword before this trait
|
LL | impl dyn Foo<i64> {
| +++
help: you might have intended to implement this trait for a given type
|
LL | impl Foo<i64> for /* Type */ {
| ++++++++++++++
```
