use `Self` alias in self types rather than manually substituting it
Of the rougly 145 uses of `self: Ty` in the standard library, 5 of them don't use `Self` but instead choose to manually "substitute" the `impl`'s self type into the type.
This leads to weird behavior sometimes (https://github.com/rust-lang/rust/issues/140611#issuecomment-2883761300) -- **to be clear**, none of these usages actually trigger any bugs, but it's possible that they may break in the future (or at least lead to lints), so let's just "fix" them proactively.
`core_float_math`: Move functions to `math` module
When these functions were added in https://github.com/rust-lang/rust/pull/138087 It made a relatively common pattern for emulating these functions using an extension trait (which internally uses `libm`) much more fragile. If `core::f32` happened to be imported by the user (to access a constant, say), then that import in the module namespace would take precedence over the `f32` in the type namespace for resolving these functions, running headfirst into the stability attribute.
We ran into this in [Color](https://github.com/linebender/color) and chose to release the remedial 0.3.1 and 0.2.4, to allow downstream crates to build on `docs.rs`.
As these methods are perma-unstable, moving them into a new module should not have any long-term concerns, and ensures that this "breakage" doesn't adversely impact anyone else.
I believe that I've made the module unstable correctly. I presume that this does not require a test to make sure stable code can't depend on the module existing?
I've left the stability attribute on each function - happy to tweak this if a different pattern is more correct.
Tracking issue for `core_float_math`: https://github.com/rust-lang/rust/issues/137578.
This PR is as requested in https://github.com/rust-lang/rust/pull/138087.
r? `@tgross35`
Recommended reviewing with whitespace hidden.
(This is my first PR to `std/core`/this repository, as far as I can remember)
When these functions were added in
https://github.com/rust-lang/rust/pull/138087
It made a relatively common pattern for emulating
these functions using an extension trait (which
internally uses `libm`) much more fragile.
If `core::f32` happened to be imported by the user
(to access a constant, say), then that import in
the module namespace would take precedence over
`f32` in the type namespace for resolving these
functions, running headfirst into the stability
attribute.
We ran into this in Color -
https://github.com/linebender/color - and chose to
release the remedial 0.3.1 and 0.2.4, to allow
downstream crates to build on `docs.rs`.
As these methods are perma-unstable, moving them
into a new module should not have any long-term
concerns, and ensures that this breakage doesn't
adversely impact anyone else.
Replace `try_reserve_exact` with `try_with_capacity` in `std::fs::read`
This change restores the previous behavior prior to #117925. That PR was made to handle OOM errors that turn into a panic with `Vec::with_capacity`. `try_reserve_exact` was used for that since there was no `try_with_capacity` method at the time. It was added later in #120504. I think it'd a better fit here.
fix data race in ReentrantLock fallback for targets without 64bit atomics
See [Zulip](https://rust-lang.zulipchat.com/#narrow/channel/269128-miri/topic/reentrant.20lock.20failure.20on.20musl) for details: the address used to identify a thread might get lazily allocated inside `tls_addr()`, so if we call that *after* doing the `tls_addr.load()` it is too late to establish synchronization with prior threads that used the same address -- the `load()` thus races with the `store()` by that prior thread, and might hence see outdated values, and then the entire logic breaks down.
r? `@joboet`
Extend the existing tests for `f32` and `f64` with versions that include
`f16`'s new printing and parsing implementations.
Co-authored-by: Speedy_Lex <alex.ciocildau@gmail.com>
std: stop using TLS in signal handler
TLS is not async-signal-safe, making its use in the signal handler used to detect stack overflows unsound (c.f. #133698). POSIX however lists two thread-specific identifiers that can be obtained in a signal handler: the current `pthread_t` and the address of `errno`. Since `pthread_equal` is not AS-safe, `pthread_t` should be considered opaque, so for our purposes, `&errno` is the only option. This however works nicely: we can use the address as a key into a map that stores information for each thread. This PR uses a `BTreeMap` protected by a spin lock to hold the guard page address and thread name and thus fixes#133698.
Stabilize the avx512 target features
This PR stabilizes the AVX512 target features - see [this comment](https://github.com/rust-lang/rust/issues/111137#issuecomment-2745821279).
Tracking Issue - #44839
The target feature UI tests have been changed to `x87` (chosen because this is very unlikely to stablize ever, please comment if some other feature will be better)
related: #111137
Use the existing Lemire (decimal -> float) and Dragon / Grisu algorithms
(float -> decimal) to add support for `f16`. This allows updating the
implementation for `Display` to the expected behavior for `Display`
(currently it prints the a hex bitwise representation), matching other
floats, and adds a `FromStr` implementation.
In order to avoid crashes when compiling with Cranelift or on targets
where f16 is not well supported, a fallback is used if
`cfg(target_has_reliable_f16)` is not true.
Remove #![feature(let_chains)] from library and src/librustdoc
PR https://github.com/rust-lang/rust/pull/132833 has stabilized the `let_chains` feature. This PR removes the last occurences from the library, the compiler, and librustdoc (also because #140887 missed the conditional in one of the crates as it was behind the "rustc" feature).
We keep `core` as exercise for the future as updating it is non-trivial (see PR thread).
Initial implementation of `core_float_math`
Since [1], `compiler-builtins` makes a certain set of math symbols
weakly available on all platforms. This means we can begin exposing some
of the related functions in `core`, so begin this process here.
It is not possible to provide inherent methods in both `core` and `std`
while giving them different stability gates, so standalone functions are
added instead. This provides a way to experiment with the functionality
while unstable; once it is time to stabilize, they can be converted to
inherent.
For `f16` and `f128`, everything is unstable so we can move the inherent
methods.
The following are included to start:
* floor
* ceil
* round
* round_ties_even
* trunc
* fract
* mul_add
* div_euclid
* rem_euclid
* powi
* sqrt
* abs_sub
* cbrt
These mirror the set of functions that we have in `compiler-builtins`
since [1], with the exception of `powi` that has been there longer.
Details for each of the changes is in the commit messages.
Tracking issue: https://github.com/rust-lang/rust/issues/137578
[1]: https://github.com/rust-lang/compiler-builtins/pull/763
try-job: aarch64-gnu
tru-job: armhf-gnu
try-job: i686-msvc-1
try-job: test-various
try-job: x86_64-mingw-1
try-job: x86_64-mingw-2
deduplicate abort implementations
Currently, the code for process aborts is duplicated across `panic_abort` and `std`. This PR uses `#[rustc_std_internal_symbol]` to make the `std` implementation available to `panic_abort` via the linker, thereby deduplicating the code.
Add as_ascii_unchecked() methods to char, u8, and str
This PR adds the `as_ascii_unchecked()` method to `char`, `u8`, and `str`, allowing users to convert these types to `ascii::Char`s (see #110998) in an `unsafe` context without first checking for validity. This method was already available for `[u8]`, so this PR makes the API more consistent across other types.
Add `#[must_use]` to Array::map
The output of Array::map is intended to be an array of the same size, and does not modify the original in place nor is it intended for side-effects. Thus, under normal circumstances it should be consumed.
See [discussion](https://internals.rust-lang.org/t/array-map-annotate-with-must-use/22813/26).
Attaching to tracking issue #75243
std: explain prefer `TryInto` over `TryFrom` when specifying traits bounds on generic function
Fixes#140761
This PR keeps the explanations of `Into` and `From` consistent and adds explanations for `TryInto` and `TryFrom`.
r? libs
docs(library/core/src/pin): fix typo "necessarily" -> "necessary"
Fix a typo in [`library/core/src/pin.rs`](14662fabeb/library/core/src/pin.rs), from
> As we'll see later, this is **necessarily** from the time the value is first pinned until the end of its lifespan.
to
> As we'll see later, this is **necessary** from the time the value is first pinned until the end of its lifespan.
(my emphasis).
Currently, the code for process aborts is duplicated across `panic_abort` and `std`. This PR uses `#[rustc_std_internal_symbol]` to make the `std` implementation available to `panic_abort` via the linker, thereby deduplicating the code.
MaybeUninit::write: fix doc
# Fix doc for `MaybeUninit::write`
The documentation refers to the way `MaybeUninit` stores data internally. The property of not dropping content on context exit is the responsibility of `ManuallyDrop`.
The previous commit moved all test files from `std` to `core` so git
understands the move. Not all functionality is actually testable in
`core`, however, so perform move the relevant portions back. Changes
from inherent to module methods is also done since this is the form of
math operations available in `core` (as `core_float_math`).
