Add some links to the cell docs.
This adds a few links to the cell module docs to make it a little easier to navigate to the types and functions it references.
Fix bug with assert!() calling the wrong edition of panic!().
The span of `panic!` produced by the `assert` macro did not carry the right edition. This changes `assert` to call the right version.
Also adds tests for the 2021 edition of panic and assert, that would've caught this.
Add doc aliases for "delete"
This patch adds doc aliases for "delete". The added aliases are supposed to reference usages `delete` in other programming languages.
- `HashMap::remove`, `BTreeMap::remove` -> `Map#delete` and `delete` keyword in JavaScript.
- `HashSet::remove`, `BTreeSet::remove` -> `Set#delete` in JavaScript.
- `mem::drop` -> `delete` keyword in C++.
- `fs::remove_file`, `fs::remove_dir`, `fs::remove_dir_all`-> `File#delete` in Java, `File#delete` and `Dir#delete` in Ruby.
Before this change, searching for "delete" in documentation returned no results.
sys: use `process::abort()` instead of `arch::wasm32::unreachable()`
Rationale:
- `abort()` lowers to `wasm32::unreachable()` anyway.
- `abort()` isn't `unsafe`.
- `abort()` matches the comment better.
- `abort()` avoids confusion by future readers (e.g. https://github.com/rust-lang/rust/pull/81527): the naming of wasm's `unreachable` instruction is a bit unfortunate because it is not related to the `unreachable()` intrinsic (intended to trigger UB).
Codegen is likely to be different since `unreachable()` is `inline` while `abort()` is `cold`. Since it doesn't look like we are expecting here to trigger this case, the latter seems better anyway.
Add AArch64 big-endian and ILP32 targets
This PR adds 3 new AArch64 targets:
- `aarch64_be-unknown-linux-gnu`
- `aarch64-unknown-linux-gnu_ilp32`
- `aarch64_be-unknown-linux-gnu_ilp32`
It also fixes some ABI issues on big-endian ARM and AArch64.
add `Vec::extend_from_within` method under `vec_extend_from_within` feature gate
Implement <https://github.com/rust-lang/rfcs/pull/2714>
### tl;dr
This PR adds a `extend_from_within` method to `Vec` which allows copying elements from a range to the end:
```rust
#![feature(vec_extend_from_within)]
let mut vec = vec![0, 1, 2, 3, 4];
vec.extend_from_within(2..);
assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4]);
vec.extend_from_within(..2);
assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4, 0, 1]);
vec.extend_from_within(4..8);
assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4, 0, 1, 4, 2, 3, 4]);
```
### Implementation notes
Originally I've copied `@Shnatsel's` [implementation](690742a0de/src/lib.rs (L74)) with some minor changes to support other ranges:
```rust
pub fn append_from_within<R>(&mut self, src: R)
where
T: Copy,
R: RangeBounds<usize>,
{
let len = self.len();
let Range { start, end } = src.assert_len(len);;
let count = end - start;
self.reserve(count);
unsafe {
// This is safe because `reserve()` above succeeded,
// so `self.len() + count` did not overflow usize
ptr::copy_nonoverlapping(
self.get_unchecked(src.start),
self.as_mut_ptr().add(len),
count,
);
self.set_len(len + count);
}
}
```
But then I've realized that this duplicates most of the code from (private) `Vec::append_elements`, so I've used it instead.
Then I've applied `@KodrAus` suggestions from https://github.com/rust-lang/rust/pull/79015#issuecomment-727200852.
Fix calling convention for CRT startup
My PR #81478 used the wrong calling convention for a set of
functions that are called by the CRT. These functions need to use
`extern "C"`.
This would only affect x86, which is the only target (that I know of)
that has multiple calling conventions.
```@bors``` r? ```@m-ou-se```
Let io::copy reuse BufWriter buffers
This optimization will allow users to implicitly set the buffer size for io::copy by wrapping the writer into a `BufWriter` if the default block size is insufficient, which should fix#49921
Due to min_specialization limitations this approach only works with `BufWriter` but not for `BufReader<R>` since `R` is unconstrained and thus the necessary specialization on `R: Read` is not always applicable. Once specialization becomes more powerful this optimization could be extended to look at the reader and writer side and use whichever buffer is larger.
Implement Rust 2021 panic
This implements the Rust 2021 versions of `panic!()`. See https://github.com/rust-lang/rust/issues/80162 and https://github.com/rust-lang/rfcs/pull/3007.
It does so by replacing `{std, core}::panic!()` by a bulitin macro that expands to either `$crate::panic::panic_2015!(..)` or `$crate::panic::panic_2021!(..)` depending on the edition of the caller.
This does not yet make std's panic an alias for core's panic on Rust 2021 as the RFC proposes. That will be a separate change: c5273bdfb2 That change is blocked on figuring out what to do with https://github.com/rust-lang/rust/issues/80846 first.
Implement <https://github.com/rust-lang/rfcs/pull/2714>, changes from the RFC:
- Rename the method `append_from_within` => `extend_from_within`
- Loose :Copy bound => :Clone
- Specialize in case of :Copy
This commit also adds `Vec::split_at_spare` private method and use it to implement
`Vec::spare_capacity_mut` and `Vec::extend_from_within`. This method returns 2
slices - initialized elements (same as `&mut vec[..]`) and uninitialized but
allocated space (same as `vec.spare_capacity_mut()`).
My PR #81478 used the wrong calling convention for a set of
functions that are called by the CRT. These functions need to use
`extern "C"`.
This would only affect x86, which is the only target (that I know of)
that has multiple calling conventions.
Remove const_in_array_repeat
Fixes#80371. Fixes#81315. Fixes#80767. Fixes#75682.
I thought there might be some issue with `Repeats(_, 0)`, but if you increase the items in the array it still ICEs. I'm not sure if this is the best fix but it does fix the given issue.
This patch adds doc aliases for "delete". The added aliases are
supposed to reference usages `delete` in other programming
languages.
- `HashMap::remove`, `BTreeMap::remove` -> `Map#delete` and `delete`
keyword in JavaScript.
- `HashSet::remove`, `BTreeSet::remove` -> `Set#delete` in JavaScript.
- `mem::drop` -> `delete` keyword in C++.
- `fs::remove_file`, `fs::remove_dir`, `fs::remove_dir_all`
-> `File#delete` in Java, `File#delete` and `Dir#delete` in Ruby.
Before this change, searching for "delete" in documentation
returned no results.
Resolve DLL imports at CRT startup, not on demand
On Windows, libstd uses GetProcAddress to locate some DLL imports, so
that libstd can run on older versions of Windows. If a given DLL import
is not present, then libstd uses other behavior (such as fallback
implementations).
This commit uses a feature of the Windows CRT to do these DLL imports
during module initialization, before main() (or DllMain()) is called.
This is the ideal time to resolve imports, because the module is
effectively single-threaded at that point; no other threads can
touch the data or code of the module that is being initialized.
This avoids several problems. First, it makes the cost of performing
the DLL import lookups deterministic. Right now, the DLL imports are
done on demand, which means that application threads _might_ have to
do the DLL import during some time-sensitive operation. This is a
small source of unpredictability. Since threads can race, it's even
possible to have more than one thread running the same redundant
DLL lookup.
This commit also removes using the heap to allocate strings, during
the DLL lookups.
Optimize decimal formatting of 128-bit integers
## Description
This PR optimizes the `udivmod_1e19` function, which is used for formatting 128-bit integers, based on the algorithm provided in \[1\]. This optimization improves performance of formatting 128-bit integers, especially on 64-bit architectures. It also slightly reduces the output binary size.
## Assembler comparison
https://godbolt.org/z/YrG5zY
## Performance
#### previous results
```
test fmt::write_u128_max ... bench: 552 ns/iter (+/- 4)
test fmt::write_u128_min ... bench: 125 ns/iter (+/- 2)
```
#### new results
```
test fmt::write_u128_max ... bench: 205 ns/iter (+/- 13)
test fmt::write_u128_min ... bench: 129 ns/iter (+/- 5)
```
## Reference
\[1\] T. Granlund and P. Montgomery, “Division by Invariant Integers Using Multiplication” in Proc. of the SIGPLAN94 Conference on Programming Language Design and Implementation, 1994, pp. 61–72
Remove requirement that forces symmetric and transitive PartialEq impls to exist
### Counterexample of symmetry:
If you [have](https://docs.rs/proc-macro2/1.0.24/proc_macro2/struct.Ident.html#impl-PartialEq%3CT%3E) an impl like:
```rust
impl<T> PartialEq<T> for Ident
where
T: ?Sized + AsRef<str>
```
then Rust will not even allow the symmetric impl to exist.
```console
error[E0210]: type parameter `T` must be covered by another type when it appears before the first local type (`Ident`)
--> src/main.rs:9:6
|
9 | impl<T> PartialEq<Ident> for T where T: ?Sized + AsRef<str> {
| ^ type parameter `T` must be covered by another type when it appears before the first local type (`Ident`)
|
= note: implementing a foreign trait is only possible if at least one of the types for which it is implemented is local, and no uncovered type parameters appear before that first local type
= note: in this case, 'before' refers to the following order: `impl<..> ForeignTrait<T1, ..., Tn> for T0`, where `T0` is the first and `Tn` is the last
```
<br>
### Counterexample of transitivity:
Consider these two existing impls from `regex` and `clap`:
```rust
// regex
/// An inline representation of `Option<char>`.
pub struct Char(u32);
impl PartialEq<char> for Char {
fn eq(&self, other: &char) -> bool {
self.0 == *other as u32
}
}
```
```rust
// clap
pub(crate) enum KeyType {
Short(char),
Long(OsString),
Position(u64),
}
impl PartialEq<char> for KeyType {
fn eq(&self, rhs: &char) -> bool {
match self {
KeyType::Short(c) => c == rhs,
_ => false,
}
}
}
```
It's nice to be able to add `PartialEq<proc_macro::Punct> for char` in libproc_macro (https://github.com/rust-lang/rust/pull/80595), but it makes no sense to force an `impl PartialEq<Punct> for Char` and `impl PartialEq<Punct> for KeyType` in `regex` and `clap` in code that otherwise has nothing to do with proc macros.
<br>
`@rust-lang/libs`
Stabilize `core::slice::fill_with`
_Tracking issue: https://github.com/rust-lang/rust/issues/79221_
This stabilizes the `slice_fill_with` feature for Rust 1.51, following the stabilization of `slice_fill` in 1.50. This was requested by libs team members in https://github.com/rust-lang/rust/pull/79213.
This PR also adds the "memset" alias for `slice::fill_with`, mirroring the alias set on the `slice::fill` sibling API. This will ensure someone looking for "memset" will find both variants.
r? `@Amanieu`
Stabilize by-value `[T; N]` iterator `core::array::IntoIter`
Tracking issue: https://github.com/rust-lang/rust/issues/65798
This is unblocked now that `min_const_generics` has been stabilized in https://github.com/rust-lang/rust/pull/79135.
This PR does *not* include the corresponding `IntoIterator` impl, which is https://github.com/rust-lang/rust/pull/65819. Instead, an iterator can be constructed through the `new` method.
`new` would become unnecessary when `IntoIterator` is implemented and might be deprecated then, although it will stay stable.
Implement missing `AsMut<str>` for `str`
Allows `&mut str` to be taken by a Generic which requires `T` such that `T: AsMut<str>`. Motivating example:
```rust
impl<'i, T> From<T> for StructImmut<'i> where
T: AsRef<str> + 'i,
{
fn from(asref: T) -> Self {
let string: &str = asref.as_ref();
// ...
}
}
impl<'i, T> From<T> for StructMut<'i> where
T: AsMut<str> + 'i,
{
fn from(mut asmut: T) -> Self {
let string: &mut str = asmut.as_mut();
// ...
}
}
```
The Immutable form of this structure can be constructed by `StructImmut::from(s)` where `s` may be a `&String` or a `&str`, because `AsRef<str>` is implemented for `str`. However, the mutable form of the structure can be constructed in the same way **only** with a `&mut String`, and **not** with a `&mut str`.
This change does have some precedent, because as can be seen in [the Implementors](https://doc.rust-lang.org/std/convert/trait.AsMut.html#implementors), `AsMut<[T]>` is implemented for `[T]` as well as for `Vec<T>`, but `AsMut<str>` is implemented only for `String`. This would complete the symmetry.
As a trait implementation, this should be immediately stable.
stabilise `cargo test -- --include-ignored`
stabilise `cargo test -- --include-ignored`
On stable there's no way to run ignored tests as well as the normal tests.
An example use case where stabilising this would help:
Exercism has some initial tests and then some additional ignored tests that people run currently with --ignore but currently they can't run all the tests in one go without being on nightly. It would be a little more ergonomic if this flag was stablilised.
( Fixes #65770 )
I built with ./x.py build -i library/test - but as libtest is a dylib is there an easy way to invoke it manually to check it's working as expected? (I've updated the automated tests.)
