std: refactor explanation of `NonNull`
Fixesrust-lang/rust#141933
I cut out the excessive explanation and used an example to explain how to maintain invariance, but I think what is quoted in the *rust reference* in the document needs to be added with a more layman's explanation and example.
(I'm not sure if I deleted too much)
r? `@workingjubilee`
more information to Display implementation for BorrowError/BorrowMutError
- The BorrowError/BorrowMutError Debug implementations do not print
anything differently from what the derived implementation does, so we
don't need it.
- This change also adds the location field of
BorrowError/BorrowMutError to the the Display output when it is
present, rewords the error message, and uses the Display trait for
outputting the error message instead of Debug.
Add documentation for `PathBuf`'s `FromIterator` and `Extend` impls
I think it's not very obvious that `PathBuf`'s `Extend` and `FromIterator` impls work like `PathBuf::push`, so I think these should be documented.
I'm not very happy with the wording and examples, open to suggestions :)
float tests: deduplicate min, max, and rounding tests
Part of https://github.com/rust-lang/rust/issues/141726
Best reviewed commit-by-commit.
- Use `assert_biteq!` in the `mod.rs` tests. This requires some trickery to make shadowing macros with imports work.
- The min, max, minimum, maximum tests in `tests/floats/f*.rs` are entirely subsumed by what we already have in `tests/float/mod.rs`, so I just removed them.
- The rounding tests (floor etc) in `f*.rs` had more test points, so I copied them over. They didn't have `0.5` and `-0.5` though which seem like interesting points in particular regarding the sign of the resulting zero if that's what it sounds to, and they didn't max min/max/inf/nan tests, so this was really a merger of both tests.
r? ``@tgross35``
Unimplement unsized_locals
Implements https://github.com/rust-lang/compiler-team/issues/630
Tracking issue here: https://github.com/rust-lang/rust/issues/111942
Note that this just removes the feature, not the implementation, and does not touch `unsized_fn_params`. This is because it is required to support `Box<dyn FnOnce()>: FnOnce()`.
There may be more that should be removed (possibly in follow up prs)
- the `forget_unsized` function and `forget` intrinsic.
- the `unsized_locals` test directory; I've just fixed up the tests for now
- various codegen support for unsized values and allocas
cc ``@JakobDegen`` ``@oli-obk`` ``@Noratrieb`` ``@programmerjake`` ``@bjorn3``
``@rustbot`` label F-unsized_locals
Fixesrust-lang/rust#79409
Out-of-tree testing is broken with the most recent update from
rust-lang/rust because it makes `compiler-builtins` depend on `core` by
path, which isn't usually available. In order to enable testing outside
of rust-lang/rust, add a new crate `builtins-shim` that uses the same
source as `compiler-builtins` but drops the `core` dependency. This has
replaced `compiler-builtins` as the workspace member and entrypoint for
tests.
Remove "intermittent" wording from `ReadDir`
`ReadDir` claims that `next` will return an error "if there’s some sort of intermittent IO error during iteration". I'm really not sure what this was intended to mean but the implementations will simply return all OS errors encountered during iteration to the user. What else can they do?
This is technically a change in the documented API but seeing as how it doesn't bear any relationship with the implementation I don't think it needs a libs-api fcp.
doc: mention that intrinsics should not be called in user code
Intrinsic functions declared in `std::intrinsics` are an implementation detail and should not be called directly by the user. The compiler explicitly warns against their use in user code:
```
warning: the feature `core_intrinsics` is internal to the compiler or standard library
--> src/lib.rs:1:12
|
1 | #![feature(core_intrinsics)]
| ^^^^^^^^^^^^^^^
|
= note: using it is strongly discouraged
= note: `#[warn(internal_features)]` on by default
```
[**Playground link**]
This PR documents what the compiler warning says: these intrinsics should not be used in user code.
[**Playground link**]: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2024&gist=1c893b0698291f550bbdde0151fd221b
Use a consistent ordering for top-level manifest keys, and remove those
that are now redundant (`homapage` isn't supposed to be the same as
`repository`, and `documentation` automatically points to docs.rs now).
After adding tests, the current implementation for fminimum fails when
provided a negative zero and NaN as inputs:
---- math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f64 stdout ----
thread 'math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f64' panicked at libm/src/math/fminimum_fmaximum_num.rs:240:13:
fmaximum_num(-0x0p+0, NaN)
l: NaN (0x7ff8000000000000)
r: -0.0 (0x8000000000000000)
---- math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f32 stdout ----
thread 'math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f32' panicked at libm/src/math/fminimum_fmaximum_num.rs:240:13:
fmaximum_num(-0x0p+0, NaN)
l: NaN (0x7fc00000)
r: -0.0 (0x80000000)
Add more thorough spec tests for these functions and correct the
implementations.
Canonicalization is also moved to a trait method to centralize
documentation about what it does and doesn't do.
Intrinsic functions declared in `std::intrinsics` are an implementation
detail and should not be called directly by the user. The compiler
explicitly warns against their use in user code:
```
warning: the feature `core_intrinsics` is internal to the compiler or standard library
--> src/lib.rs:1:12
|
1 | #![feature(core_intrinsics)]
| ^^^^^^^^^^^^^^^
|
= note: using it is strongly discouraged
= note: `#[warn(internal_features)]` on by default
```
[**Playground link**]
This PR documents what the compiler warning says: these intrinsics should
not be called outside the standard library.
[**Playground link**]: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2024&gist=1c893b0698291f550bbdde0151fd221b
Rollup of 6 pull requests
Successful merges:
- rust-lang/rust#138016 (Added `Clone` implementation for `ChunkBy`)
- rust-lang/rust#141162 (refactor `AttributeGate` and `rustc_attr!` to emit notes during feature checking)
- rust-lang/rust#141474 (Add `ParseMode::Diagnostic` and fix multiline spans in diagnostic attribute lints)
- rust-lang/rust#141947 (Specify that "option-like" enums must be `#[repr(Rust)]` to be ABI-compatible with their non-1ZST field.)
- rust-lang/rust#142252 (Improve clarity of `core::sync::atomic` docs about "Considerations" in regards to CAS operations)
- rust-lang/rust#142337 (miri: add flag to suppress float non-determinism)
r? `@ghost`
`@rustbot` modify labels: rollup
Upgrade `object`, `addr2line`, and `unwinding` in the standard library
Object:
0.37.0 is a semver-breaking release but the only breakage is in `elf::R_RISCV_GNU_*` and `pe::IMAGE_WEAK_EXTERN_*` constants, as well as Mach-O dyld. This API is not used by `std`, so we should be fine to upgrade.
This new version also includes functionality for parsing Wasm object files that we may eventually like to make use of.
Changelog: https://github.com/gimli-rs/object/blob/master/CHANGELOG.md#0370
Addr2line:
0.25.0 is a breaking change only because it upgrades the `gimli` version. It also includes a change to the `compiler-builtins` dependency that helps with [1].
Changelog: https://github.com/gimli-rs/addr2line/blob/master/CHANGELOG.md#0250-20250611
[1]: https://github.com/rust-lang/rust/issues/142265
Update dependencies in `library/Cargo.lock`
This removes the `compiler_builtins` dependency from a handful of library dependencies, which is progress toward [1].
[1]: https://github.com/rust-lang/rust/issues/142265
intrinsics: rename min_align_of to align_of
Now that `pref_align_of` is gone (https://github.com/rust-lang/rust/pull/141803), we can give the intrinsic backing `align_of` its proper name.
r? `@workingjubilee` or `@bjorn3`
Tracking the old name of renamed unstable library features
This PR resolves the first problem of rust-lang/rust#141617 : tracking renamed unstable features. The first commit is to add a ui test, and the second one tracks the changes. I will comment on the code for clarification.
r? `@jdonszelmann`
There have been a lot of PR's reviewed by you lately, thanks for your time!
cc `@jyn514`
Lint on fn pointers comparisons in external macros
This PR extends the recently stabilized `unpredictable_function_pointer_comparisons` lint ~~to also lint on `Option<{function pointer}>` and~~ as well as linting in external macros (as to catch `assert_eq!` and others).
```rust
assert_eq!(Some::<FnPtr>(func), Some(func as unsafe extern "C" fn()));
//~^ WARN function pointer comparisons
#[derive(PartialEq, Eq)]
struct A {
f: fn(),
//~^ WARN function pointer comparisons
}
```
Fixes https://github.com/rust-lang/rust/issues/134527
Improve clarity of `core::sync::atomic` docs about "Considerations" in regards to CAS operations
## Motivation
The existing documentation for atomic `fetch_update` (and other similar methods) has a section that reads like so:
> ### Considerations
> This method is not magic; it is not provided by the hardware. It is implemented in
> terms of `AtomicBlah::compare_exchange_weak`, and suffers from the same drawbacks.
> In particular, this method will not circumvent the [ABA Problem].
>
> [ABA Problem]: https://en.wikipedia.org/wiki/ABA_problem
The wording here seems to imply that the drawbacks being discusses are caused by the *`weak` version* of `compare_exchange`, and that one may avoid those drawbacks by using `compare_exchange` instead. Indeed, a conversation in the `#dark-arts` channel on the Rust community discord based on this interpretation led to this PR.
In reality, the drawbacks are inherent to implementing such an operation based on *any* compare-and-swap style operation, as opposed to an [LL,SC](https://en.wikipedia.org/wiki/Load-link/store-conditional) operation, and they apply equally to `compare_exchange` and `compare_exchange_weak` as well.
## Changes
- Rewords existing Considerations section on `fetch_update` and friends to make clear that the limitations are inherent to an implementation based on any CAS operation, rather than the weak version of `compare_exchange` in particular. New version:
> ### Considerations
>
> This method is not magic; it is not provided by the hardware, and does not act like a
> critical section or mutex.
>
> It is implemented on top of an atomic [compare-and-swap operation], and thus is subject to
> the usual drawbacks of CAS operations. In particular, be careful of the [ABA problem]
> if this atomic integer is an index or more generally if knowledge of only the *bitwise value*
> of the atomic is not in and of itself sufficient to ensure any required preconditions.
>
> [ABA Problem]: https://en.wikipedia.org/wiki/ABA_problem
> [compare-and-swap operation]: https://en.wikipedia.org/wiki/Compare-and-swap
- Add Considerations to `compare_exchange` and `compare_exchange_weak` which details similar considerations and when they may be relevant. New version:
> ### Considerations
>
> `compare_exchange` is a [compare-and-swap operation] and thus exhibits the usual downsides
> of CAS operations. In particular, a load of the value followed by a successful
> `compare_exchange` with the previous load *does not ensure* that other threads have not
> changed the value in the interim. This is usually important when the *equality* check in
> the `compare_exchange` is being used to check the *identity* of a value, but equality
> does not necessarily imply identity. In this case, `compare_exchange` can lead to the
> [ABA problem].
>
> [ABA Problem]: https://en.wikipedia.org/wiki/ABA_problem
> [compare-and-swap operation]: https://en.wikipedia.org/wiki/Compare-and-swap
