Remove len argument from RawVec::reserve_for_push
Removes `RawVec::reserve_for_push`'s `len` argument since it's always the same as capacity.
Also makes `Vec::insert` use `RawVec::reserve_for_push`.
Stabilize `unchecked_{add,sub,mul}`
Tracking issue: #85122
I think we might as well just stabilize these basic three. They're the ones that have `nuw`/`nsw` flags in LLVM.
Notably, this doesn't include the potentially-more-complex or -more-situational things like `unchecked_neg` or `unchecked_shr` that are under different feature flags.
To quote Ralf https://github.com/rust-lang/rust/issues/85122#issuecomment-1681669646,
> Are there any objections to stabilizing at least `unchecked_{add,sub,mul}`? For those there shouldn't be any surprises about what their safety requirements are.
*Semantially* these are [already available on stable, even in `const`, via](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=bdb1ff889b61950897f1e9f56d0c9a36) `checked_*`+`unreachable_unchecked`. So IMHO we might as well just let people write them directly, rather than try to go through a `let Some(x) = x.checked_add(y) else { unsafe { hint::unreachable_unchecked() }};` dance.
I added additional text to each method to attempt to better describe the behaviour and encourage `wrapping_*` instead.
r? rust-lang/libs-api
Add detection of [Partial]Ord methods in the `ambiguous_wide_pointer_comparisons` lint
Partially addresses https://github.com/rust-lang/rust/issues/121264 by adding diagnostics items for PartialOrd and Ord methods, detecting such diagnostics items as "binary operation" and suggesting the correct replacement.
I also took the opportunity to change the suggestion to use new methods `.cast()` on `*mut T` an d `*const T`.
Eliminate `UbChecks` for non-standard libraries
The purpose of this PR is to allow other passes to treat `UbChecks` as constants in MIR for optimization after #122629.
r? RalfJung
Codegen const panic messages as function calls
This skips emitting extra arguments at every callsite (of which there
can be many). For a librustc_driver build with overflow checks enabled,
this cuts 0.7MB from the resulting shared library (see [perf]).
A sample improvement from nightly:
```
leaq str.0(%rip), %rdi
leaq .Lalloc_d6aeb8e2aa19de39a7f0e861c998af13(%rip), %rdx
movl $25, %esi
callq *_ZN4core9panicking5panic17h17cabb89c5bcc999E@GOTPCREL(%rip)
```
to this PR:
```
leaq .Lalloc_d6aeb8e2aa19de39a7f0e861c998af13(%rip), %rdi
callq *_RNvNtNtCsduqIKoij8JB_4core9panicking11panic_const23panic_const_div_by_zero@GOTPCREL(%rip)
```
[perf]: https://perf.rust-lang.org/compare.html?start=a7e4de13c1785819f4d61da41f6704ed69d5f203&end=64fbb4f0b2d621ff46d559d1e9f5ad89a8d7789b&stat=instructions:u
`num::NonZero::get` can be 1 transmute instead of 2
Just something I noticed in passing. No need for a `match` in here to call `unreachable_unchecked`, as `transmute_unchecked` will add the appropriate `llvm.assume` <https://rust.godbolt.org/z/W5hjeETnc>.
Clarify atomic bit validity
The previous definition used the phrase "representation", which is ambiguous given the current state of memory model nomenclature in Rust. For integer types and for `AtomicPtr<T>`, the new wording clarifies that size and bit validity are guaranteed to match the corresponding native integer type/`*mut T`. For `AtomicBool`, the new wording clarifies that size, alignment, and bit validity are guaranteed to match `bool`.
Note that we use the phrase "size and alignment" rather than "layout" since the latter term also implies that the field types are the same. This isn't true - `AtomicXxx` doesn't store an `xxx`, but rather an `UnsafeCell<xxx>`. This distinction is important for some `unsafe` code, which needs to reason about the presence or absence of interior mutability in order to ensure that their code is sound (see e.g. https://github.com/google/zerocopy/issues/251).
Soft-destabilize `RustcEncodable` & `RustcDecodable`, remove from prelude in next edition
cc rust-lang/libs-team#272
Any use of `RustcEncodable` and `RustcDecodable` now triggers a deny-by-default lint. The derives have been removed from the 2024 prelude. I specifically chose **not** to document this in the module-level documentation, as the presence in existing preludes is not documented (which I presume is intentional).
This does not implement the proposed change for `rustfix`, which I will be looking into shortly.
With regard to the items in the preludes being stable, this should not be an issue because #15702 has been resolved.
r? libs-api
Update `RwLock` deadlock example to not use shadowing
Tweak variable names in the deadlock example to remove any potential confusion that the behavior is somehow shadowing-related.
Implement `Vec::pop_if`
This PR adds `Vec::pop_if` to the public API, behind the `vec_pop_if` feature.
```rust
impl<T> Vec<T> {
pub fn pop_if<F>(&mut self, f: F) -> Option<T>
where F: FnOnce(&mut T) -> bool;
}
```
Tracking issue: #122741
## Open questions
- [ ] Should the first unit test be split up?
- [ ] I don't see any guidance on ordering of methods in impl blocks, should I move the method elsewhere?
unix fs: Make hurd using explicit new rather than From
408c0ea216 ("unix time module now return result") dropped the From impl for SystemTime, breaking the hurd build (and probably the horizon build)
Fixes#123032
Fix doc link to BufWriter in std::fs::File documentation
It seems that doc link to `BufWriter` in `std::fs::File` doc leads to `BufReader`, not `BufWriter`.
See https://doc.rust-lang.org/std/fs/struct.File.html
Simplify proc macro bridge state
Currently, `proc_macro` uses a `ScopedCell` to store the client-side proc-macro bridge. Unfortunately, this requires the `Bridge`, which has non-negligible size, to be copied out and back again on every access. In some cases, the optimizer might be able to elide these copies, but in general, this is suboptimal.
This PR removes `ScopedCell` and employs a similar trick as in [`scoped_tls`](https://crates.io/crates/scoped-tls), meaning that the only thing stored in TLS is a pointer to the state, which now is a `RefCell`. Access to the pointer is then scoped so that it is always within the lifetime of the reference to the state. Unfortunately, `scoped_tls` requires the referenced type to be `'static`, which `Bridge` is not, therefore we cannot simply copy that macro but have to reimplement its TLS trick.
This removes the `#[forbid(unsafe_code)]` on the `client` module so that we do not have to export `Bridge`, which currently is private, to the whole crate. I can change that, if necessary.
