introduce `{char, u8}::is_ascii_octdigit`
This feature adds two new APIs: `char::is_ascii_octdigit` and `u8::is_ascii_octdigit`, under the feature gate `is_ascii_octdigit`. These methods are shorthands for `char::is_digit(self, 8)` and `u8::is_digit(self, 8)`:
```rust
// core::char
impl char {
pub fn is_ascii_octdigit(self) -> bool;
}
// core::num
impl u8 {
pub fn is_ascii_octdigit(self) -> bool;
}
```
---
Couple of things I need help understanding:
- `const`ness: have I used the right attribute in this case?
- is there a way to run the tests for `core::char` alone, instead of `./x.py test library/core`?
docs: Improve AsRef / AsMut docs on blanket impls
There are several issues with the current state of `AsRef` and `AsMut` as [discussed here on IRLO](https://internals.rust-lang.org/t/semantics-of-asref/17016). See also #39397, #45742, #73390, #98905, and the FIXMEs [here](https://github.com/rust-lang/rust/blob/1.62.0/library/core/src/convert/mod.rs#L509-L515) and [here](https://github.com/rust-lang/rust/blob/1.62.0/library/core/src/convert/mod.rs#L530-L536). These issues are difficult to fix. This PR aims to update the documentation to better reflect the status-quo and to give advice on how `AsRef` and `AsMut` should be used.
In particular:
- Explicitly mention that `AsRef` and `AsMut` do not auto-dereference generally for all dereferencable types (but only if inner type is a shared and/or mutable reference)
- Give advice to not use `AsRef` or `AsMut` for the sole purpose of dereferencing
- Suggest providing a transitive `AsRef` or `AsMut` implementation for types which implement `Deref`
- Add new section "Reflexivity" in documentation comments for `AsRef` and `AsMut`
- Provide better example for `AsMut`
- Added heading "Relation to `Borrow`" in `AsRef`'s docs to improve structure
Improve documentation of `slice::{from_ptr_range, from_ptr_range_mut}`
Document panic conditions (`T` is a ZST) and sync docs of shared/unique version.
cc `@wx-csy`
Improve `FromStr` example
The `from_str` implementation from the example had an `unwrap` that would make it panic on invalid input strings. Instead of panicking, it nows returns an error to better reflect the intented behavior of the `FromStr` trait.
The `from_str` implementation from the example had an `unwrap` that would make it panic on invalid input strings. Instead of panicking, it nows returns an error to better reflect the intented behavior of the `FromStr` trait.
Add negation methods for signed non-zero integers.
Performing negation with defined wrapping semantics (such as `wrapping_neg()`) on a non-zero integer currently requires unpacking to a primitive and re-wrapping. Since negation of non-zero signed integers always produces a non-zero result, it is safe to implement the various `*_neg()` methods for `NonZeroI{N}`.
I'm not sure what to do about the `#[unstable(..., issue = "none")]` here -- should I file a tracking issue, or is that handled by the Rust dev team?
ACP: https://github.com/rust-lang/libs-team/issues/105
Add a niche to `Duration`, unix `SystemTime`, and non-apple `Instant`
As the nanoseconds fields is always between `0` and `(NANOS_PER_SEC - 1)` inclusive, use the `rustc_layout_scalar_valid_range` attributes to create a niche in the nanosecond field of `Duration` and `Timespec` (which is used to implement unix `SystemTime` and non-apple unix `Instant`; windows `Instant` is implemented with `Duration` and therefore will also benefit). This change has the benefit of making `Option<T>` the same size as `T` for the previously mentioned types. Also shrinks the nanoseconds field of `Timespec` to a `u32` as nanoseconds do not need the extra range of an `i64`, shrinking `Timespec` by 4 bytes on 32-bit platforms.
r? ```@joshtriplett```
Add `#[rustc_safe_intrinsic]`
This PR adds the `#[rustc_safe_intrinsic]` attribute as mentionned on Zulip. The goal of this attribute is to avoid keeping a list of symbols as the source for stable intrinsics, and instead rely on an attribute. This is similar to `#[rustc_const_stable]` and `#[rustc_const_unstable]`, which among other things, are used to mark the constness of intrinsic functions.
Suggest unwrapping `???<T>` if a method cannot be found on it but is present on `T`.
This suggests various ways to get inside wrapper types if the method cannot be found on the wrapper type, but is present on the wrappee.
For this PR, those wrapper types include `Localkey`, `MaybeUninit`, `RefCell`, `RwLock` and `Mutex`.
Stabilize bench_black_box
This PR stabilize `feature(bench_black_box)`.
```rust
pub fn black_box<T>(dummy: T) -> T;
```
The FCP was completed in https://github.com/rust-lang/rust/issues/64102.
`@rustbot` label +T-libs-api -T-libs
Stabilize `#![feature(mixed_integer_ops)]`
Tracked and FCP completed in #87840.
````@rustbot```` label +T-libs-api +S-waiting-on-review +relnotes
r? rust-lang/t-libs-api
