There are a few places where we mention the replacement character in the
docs, and it could be helpful for users to utilize the constant which is
available in the standard library, so let’s link to it!
Rename Executor trait to Spawn
Renames the `Executor` trait to `Spawn` and the method on `Context` to `spawner`.
Note: Best only merge this after we've the alpha 3 announcement post ready.
r? @cramertj
Incorporate a stray test
`liballoc/repeat-generic-slice.rs` doesn't seem to be tested (I think it was intended to be placed in `run-pass`). This PR incorporates the test into `liballoc/tests`.
Rollup of bare_trait_objects PRs
All deny attributes were moved into bootstrap so they can be disabled with a line of config.
Warnings for external tools are allowed and it's up to the tool's maintainer to keep it warnings free.
r? @Mark-Simulacrum
cc @ljedrz @kennytm
doc: Clarify the lifetime returned by `Box::leak`
`Box::leak` mentions that it can return a `'static` reference, but it
wasn't immediately clear to me why it doesn't always do so. This is
because of the `T: 'a` constraint needed to form a valid reference, and
in general we want to be more flexible than requiring `T: 'static`.
This patch tries to clarify the relationship between `T` and `'a`.
Deprecation of str::slice_unchecked(_mut)
Closes#51715
I am not sure if 1.28.0 or 1.29.0 should be used for deprecation version, for now it's 1.28.0.
Additionally I've replaced `slice_unchecked` uses with `get_unchecked`. The only places where this method is still used are `src/liballoc/tests/str.rs` and `src/liballoc/tests/str.rs`.
Handle array manually in str case conversion methods
Avoiding the overhead incurred from `String.extend(char.to_lowercase())` showed a notable performance improvement when I benchmarked it.
I tested on these strings:
```rust
ALL_LOWER: "loremipsumdolorsitametduosensibusmnesarchumabcdefgh"
ALL_UPPER: "LOREMIPSUMDOLORSITAMETDUOSENSIBUSMNESARCHUMABCDEFGH"
REALISTIC_UPPER: "LOREM IPSUM DOLOR SIT AMET, DUO SENSIBUS MNESARCHUM"
SIGMAS: "ΣΣΣΣΣ ΣΣΣΣΣ ΣΣΣΣΣ ΣΣΣ ΣΣΣΣ, ΣΣΣ ΣΣΣΣΣΣΣΣ ΣΣΣΣΣΣΣΣΣΣ"
WORD_UPPER: "Lorem Ipsum Dolor Sit Amet, Duo Sensibus Mnesarchum"
```
the performance improvements of `to_lowercase()` were
```
running 10 tests
test tests::all_lower ... bench: 1,752 ns/iter (+/- 49)
test tests::all_lower_new ... bench: 1,266 ns/iter (+/- 15) -28%
test tests::all_upper ... bench: 1,832 ns/iter (+/- 39)
test tests::all_upper_new ... bench: 1,337 ns/iter (+/- 18) -27%
test tests::realistic_upper ... bench: 1,993 ns/iter (+/- 14)
test tests::realistic_upper_new ... bench: 1,445 ns/iter (+/- 22) -27%
test tests::sigmas ... bench: 1,342 ns/iter (+/- 39)
test tests::sigmas_new ... bench: 1,226 ns/iter (+/- 16) -9%
test tests::word_upper ... bench: 1,899 ns/iter (+/- 12)
test tests::word_upper_new ... bench: 1,381 ns/iter (+/- 26) -27%
```
and of `to_uppercase()`
```
running 10 tests
test tests::all_lower ... bench: 1,813 ns/iter (+/- 20)
test tests::all_lower_new ... bench: 1,321 ns/iter (+/- 16) -27%
test tests::all_upper ... bench: 1,629 ns/iter (+/- 22)
test tests::all_upper_new ... bench: 1,241 ns/iter (+/- 9) -24%
test tests::realistic_upper ... bench: 1,670 ns/iter (+/- 24)
test tests::realistic_upper_new ... bench: 1,241 ns/iter (+/- 17) -26%
test tests::sigmas ... bench: 2,053 ns/iter (+/- 20)
test tests::sigmas_new ... bench: 1,753 ns/iter (+/- 23) -15%
test tests::word_upper ... bench: 1,873 ns/iter (+/- 30)
test tests::word_upper_new ... bench: 1,412 ns/iter (+/- 25) -25%
```
I gave up on the more advanced method from #52061 as it wasn't always a clear improvement and would help in even less cases if this PR was merged.
`Box::leak` mentions that it can return a `'static` reference, but it
wasn't immediately clear to me why it doesn't always do so. This is
because of the `T: 'a` constraint needed to form a valid reference, and
in general we want to be more flexible than requiring `T: 'static`.
This patch tries to clarify the relationship between `T` and `'a`.
Add the `alloc::prelude` module
It contains the re-exports that are in `std::prelude::v1` but not in `core::prelude::v1`.
Calling it prelude is somewhat of a misnomer since (unlike those modules in `std` or `core`) its contents are never implicitly imported in modules. Rather it is intended to be used with an explicit glob import like `use alloc::prelude::*;`. However there is precedent for the same misnomer with `std::io::prelude`, for example.
This new module is unstable with the same feature name as the `alloc` care. They are proposed for stabilization together in RFC https://github.com/rust-lang/rfcs/pull/2480.
It contains the re-exports that are in `std::prelude::v1`
but not in `core::prelude::v1`.
Calling it prelude is somewhat of a misnomer since (unlike those modules
in `std` or `core`) its contents are never implicitly imported in modules.
Rather it is intended to be used with an explicit glob import like
`use alloc::prelude::*;`.
However there is precedent for the same misnomer with `std::io::prelude`,
for example.
This new module is unstable with the same feature name as the `alloc` care.
They are proposed for stabilization together in RFC
https://github.com/rust-lang/rfcs/pull/2480
enable Atomic*.{load,store} for ARMv6-M / MSP430
closes#45085
as proposed in https://github.com/rust-lang/rust/issues/45085#issuecomment-384825434
this commit adds an `atomic_cas` target option and extends the `#[cfg(target_has_atomic)]`
attribute to enable a subset of the `Atomic*` API on architectures that don't support atomic CAS
natively, like MSP430 and ARMv6-M.
r? @alexcrichton
closes#45085
this commit adds an `atomic_cas` target option and an unstable `#[cfg(target_has_atomic_cas)]`
attribute to enable a subset of the `Atomic*` API on architectures that don't support atomic CAS
natively, like MSP430 and ARMv6-M.
Previously, `is_unique` would not synchronize at all with a `drop` that returned
early because it was not the last reference, leading to a data race.
Fixes#51780
