We have a constant for it already (used in `RawVec` for basically the same polymorphization) so let's use it.
Conveniently, it can even be safe that way!
Pass alignments through the shim as `Alignment` (not `usize`)
We're using `Layout` on both sides, so might as well skip the transmutes back and forth to `usize`.
The mir-opt test shows that doing so allows simplifying the boxed-slice drop slightly, for example.
We're using `Layout` on both sides, so might as well skip the transmutes back and forth to `usize`.
The mir-opt test shows that doing so allows simplifying the boxed-slice drop slightly, for example.
compiler-builtins: Remove the no-f16-f128 feature
This option was used to gate `f16` and `f128` when support across backends and targets was inconsistent. We now have the rustc builtin cfg `target_has_reliable{f16,f128}` which has taken over this usecase. Remove no-f16-f128 since it is now unused and redundant.
Add some clarifications and fixes for fmt syntax
This tries to clarify a few things regarding fmt syntax:
- The comment on `Parser::word` seems to be wrong, as that underscore-prefixed words are just fine. This was changed in https://github.com/rust-lang/rust/pull/66847.
- I struggled to follow the description of the width argument. It referred to a "second argument", but I don't know what second argument it is referring to (which is the first?). Either way, I rewrote the paragraph to try to be a little more explicit, and to use shorter sentences.
- The description of the precision argument wasn't really clear about the distinction of an Nth argument and a named argument. I added a sentence to try to emphasize the difference.
- `IDENTIFIER_OR_KEYWORD` was changed recently in https://github.com/rust-lang/reference/pull/2049 to include bare `_`. But fmt named arguments are not allowed to be a bare `_`.
remove multiple unhelpful `reason = "..."` values from `#[unstable(...)]` invocations
The vast majority of `#[unstable()]` attributes already has no explicit reason specified. This PR removes the `reason = "..."` value for the following unhelpful or meaningless reasons:
* "recently added"
* "new API"
* "recently redesigned"
* "unstable"
An example of how the message looks with and without a reason:
```rust
fn main() {
Vec::<()>::into_parts;
Vec::<()>::const_make_global;
}
```
```
error[E0658]: use of unstable library feature `box_vec_non_null`: new API
--> src/main.rs:2:5
|
2 | Vec::<()>::into_parts;
| ^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #130364 <https://github.com/rust-lang/rust/issues/130364> for more information
= help: add `#![feature(box_vec_non_null)]` to the crate attributes to enable
= note: this compiler was built on 2026-01-15; consider upgrading it if it is out of date
error[E0658]: use of unstable library feature `const_heap`
--> src/main.rs:3:5
|
3 | Vec::<()>::const_make_global;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #79597 <https://github.com/rust-lang/rust/issues/79597> for more information
= help: add `#![feature(const_heap)]` to the crate attributes to enable
= note: this compiler was built on 2026-01-15; consider upgrading it if it is out of date
```
Most of the remaining reasons after this are something similar to "this is an implementation detail for XYZ" or "this is not public". If this PR is approved, I'll look into those next.
The PR also removes the `fd_read` feature gate. It only consists of one attribute applied to an implementation inside a module that is already private and unstable and should not be needed.
This reverts PR <https://github.com/rust-lang/rust/pull/130998> because
the added test seems to be flaky / non-deterministic, and has been
failing in unrelated PRs during merge CI.
This tries to clarify a few things regarding fmt syntax:
- The comment on `Parser::word` seems to be wrong, as that
underscore-prefixed words are just fine. This was changed in
https://github.com/rust-lang/rust/pull/66847.
- I struggled to follow the description of the width argument. It
referred to a "second argument", but I don't know what second argument
it is referring to (which is the first?). Either way, I rewrote the
paragraph to try to be a little more explicit, and to use shorter
sentences.
- The description of the precision argument wasn't really clear about
the distinction of an Nth argument and a named argument. I added
a sentence to try to emphasize the difference.
- `IDENTIFIER_OR_KEYWORD` was changed recently in
https://github.com/rust-lang/reference/pull/2049 to include bare `_`.
But fmt named arguments are not allowed to be a bare `_`.
This option was used to gate `f16` and `f128` when support across
backends and targets was inconsistent. We now have the rustc builtin cfg
`target_has_reliable{f16,f128}` which has taken over this usecase.
Remove no-f16-f128 since it is now unused and redundant.
bors