Update bootstrap compiler and rustfmt
The rustfmt version we previously used formats things differently from what the latest nightly rustfmt does. This causes issues for subtrees that get formatted both in-tree and in their own repo. Updating the rustfmt used in-tree solves those issues. Also bumped the bootstrap compiler as the stage0 update command always updates both at the same
time.
Optimize `Rc::<str>::default()` implementation
This PR lets `impl Default for Rc<str>` re-use the implementation for `Rc::<[u8]>::default()`. The previous version only calculted the memory layout at runtime, even though it should be known at compile time, resulting in an additional function call.
The same optimization is done for `Rc<CStr>`.
Generated byte code: <https://godbolt.org/z/dfq73jsoP>.
Resolves <https://github.com/rust-lang/rust/issues/135784>.
Cc `@Billy-Sheppard.`
* Renames the methods:
* `get_many_mut` -> `get_disjoint_mut`
* `get_many_unchecked_mut` -> `get_disjoint_unchecked_mut`
* Does not rename the feature flag: `get_many_mut`
* Marks the feature as stable
* Renames some helper stuff:
* `GetManyMutError` -> `GetDisjointMutError`
* `GetManyMutIndex` -> `GetDisjointMutIndex`
* `get_many_mut_helpers` -> `get_disjoint_mut_helpers`
* `get_many_check_valid` -> `get_disjoint_check_valid`
This only touches slice methods.
HashMap's methods and feature gates are not renamed here
(nor are they stabilized).
Add missing allocator safety in alloc crate
### PR Description
In the previous PR [#135009](https://github.com/rust-lang/rust/pull/135009), PR [#134496](https://github.com/rust-lang/rust/pull/134496), some incomplete API documentation issues have been fixed.
Based on these changes, other inconsistencies related to the allocator have also been identified, including:
- `Box::from_non_null`
- `Box::from_non_null_in`
- `Weak::from_raw`
Enable `unreachable_pub` lint in `alloc`
This PR enables the [`unreachable_pub`](https://doc.rust-lang.org/rustc/lints/listing/allowed-by-default.html#unreachable-pub) lint as warn in the `alloc` crate.
Most of changes are in the btree implementation and in tests.
*The diff was mostly generated with `./x.py fix --stage 1 library/alloc/ -- --broken-code`, as well as manual edits for code in macros and in tests.*
Continuation of #134286 and #135366
r? libs
This PR lets `impl Default for Rc<str>` re-use the implementation
for `Rc::<[u8]>::default()`. The previous version only calculted the
memory layout at runtime, even though it should be known at compile
time, resulting in an additional function call.
The same optimization is done for `Rc<CStr>`.
Generated byte code: <https://godbolt.org/z/dfq73jsoP>.
Resolves <https://github.com/rust-lang/rust/issues/135784>.
The `Box::new(T::default())` implementation of `Box::default` only
had two stack copies in debug mode, compared to the current version,
which has four. By avoiding creating any `MaybeUninit<T>`'s and just writing
`T` directly to the `Box` pointer, the stack usage in debug mode remains
the same as the old version.
Implement `ByteStr` and `ByteString` types
Approved ACP: https://github.com/rust-lang/libs-team/issues/502
Tracking issue: https://github.com/rust-lang/rust/issues/134915
These types represent human-readable strings that are conventionally,
but not always, UTF-8. The `Debug` impl prints non-UTF-8 bytes using
escape sequences, and the `Display` impl uses the Unicode replacement
character.
This is a minimal implementation of these types and associated trait
impls. It does not add any helper methods to other types such as `[u8]`
or `Vec<u8>`.
I've omitted a few implementations of `AsRef`, `AsMut`, and `Borrow`,
when those would be the second implementation for a type (counting the
`T` impl), to avoid potential inference failures. We can attempt to add
more impls later in standalone commits, and run them through crater.
In addition to the `bstr` feature, I've added a `bstr_internals` feature
for APIs provided by `core` for use by `alloc` but not currently
intended for stabilization.
This API and its implementation are based *heavily* on the `bstr` crate
by Andrew Gallant (`@BurntSushi).`
r? `@BurntSushi`
Update documentation for Arc::from_raw, Arc::increment_strong_count, and Arc::decrement_strong_count to clarify allocator requirement
### Related Issue:
This update addresses parts of the issue raised in [#134242](https://github.com/rust-lang/rust/issues/134242), where Arc's documentation lacks `Global Allocator` safety descriptions for three APIs. And this was confirmed by ```@workingjubilee``` :
> Wait, nevermind. I apparently forgot the `increment_strong_count` is implicitly A = Global. Ugh. Another reason these things are hard to track, unfortunately.
### PR Description
This PR updates the document for the following APIs:
- `Arc::from_raw`
- `Arc::increment_strong_count`
- `Arc::decrement_strong_count`
These APIs currently lack an important piece of documentation: **the raw pointer must point to a block of memory allocated by the global allocator**. This crucial detail is specified in the source code but is not reflected in the documentation, which could lead to confusion or incorrect usage by users.
### Problem:
The following example demonstrates the potential confusion caused by the lack of documentation:
```rust
#![feature(allocator_api)]
use std::alloc::{Allocator,AllocError, Layout};
use std::ptr::NonNull;
use std::sync::Arc;
struct LocalAllocator {
memory: NonNull<u8>,
size: usize,
}
impl LocalAllocator {
fn new(size: usize) -> Self {
Self {
memory: unsafe { NonNull::new_unchecked(&mut 0u8 as *mut u8) },
size,
}
}
}
unsafe impl Allocator for LocalAllocator {
fn allocate(&self, _layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
Ok(NonNull::slice_from_raw_parts(self.memory, self.size))
}
unsafe fn deallocate(&self, _ptr: NonNull<u8>, _layout: Layout) {
}
}
fn main() {
let allocator = LocalAllocator::new(64);
let arc = Arc::new_in(5, &allocator); // Here, allocator could be any non-global allocator
let ptr = Arc::into_raw(arc);
unsafe {
Arc::increment_strong_count(ptr);
let arc = Arc::from_raw(ptr);
assert_eq!(2, Arc::strong_count(&arc)); // Failed here!
}
}
```
Add an example for `Vec::splice` inserting elements without removing
This example clearly showcases how `splice` can be used to insert multiple elements efficiently at an index into a vector.
Fixes#135369.
The added example:
> Using `splice` to insert new items into a vector efficiently at a specific position indicated by an empty range:
> ```rust
> let mut v = vec![1, 5];
> let new = [2, 3, 4];
> v.splice(1..1, new);
> assert_eq!(v, [1, 2, 3, 4, 5]);
> ```
`@rustbot` label A-docs A-collections
Rollup of 6 pull requests
Successful merges:
- #129259 (Add inherent versions of MaybeUninit methods for slices)
- #135374 (Suggest typo fix when trait path expression is typo'ed)
- #135377 (Make MIR cleanup for functions with impossible predicates into a real MIR pass)
- #135378 (Remove a bunch of diagnostic stashing that doesn't do anything)
- #135397 (compiletest: add erroneous variant to `string_enum`s conversions error)
- #135398 (add more crash tests)
r? `@ghost`
`@rustbot` modify labels: rollup
Use `NonNull::without_provenance` within the standard library
This API removes the need for several `unsafe` blocks, and leads to clearer code. It uses feature `nonnull_provenance` (#135243).
Close#135343
Update a bunch of library types for MCP807
This greatly reduces the number of places that actually use the `rustc_layout_scalar_valid_range_*` attributes down to just 3:
```
library/core\src\ptr\non_null.rs
68:#[rustc_layout_scalar_valid_range_start(1)]
library/core\src\num\niche_types.rs
19: #[rustc_layout_scalar_valid_range_start($low)]
20: #[rustc_layout_scalar_valid_range_end($high)]
```
Everything else -- PAL Nanoseconds, alloc's `Cap`, niched FDs, etc -- all just wrap those `niche_types` types.
r? ghost
Approved ACP: https://github.com/rust-lang/libs-team/issues/502
Tracking issue: https://github.com/rust-lang/rust/issues/134915
These types represent human-readable strings that are conventionally,
but not always, UTF-8. The `Debug` impl prints non-UTF-8 bytes using
escape sequences, and the `Display` impl uses the Unicode replacement
character.
This is a minimal implementation of these types and associated trait
impls. It does not add any helper methods to other types such as `[u8]`
or `Vec<u8>`.
I've omitted a few implementations of `AsRef`, `AsMut`, `Borrow`,
`From`, and `PartialOrd`, when those would be the second implementation
for a type (counting the `T` impl) or otherwise may cause inference
failures. These impls are important, but we can attempt to add them
later in standalone commits, and run them through crater.
In addition to the `bstr` feature, I've added a `bstr_internals` feature
for APIs provided by `core` for use by `alloc` but not currently
intended for stabilization.
This API and its implementation are based *heavily* on the `bstr` crate
by Andrew Gallant (@BurntSushi).
