move core::hint::black_box under its own feature gate
The `black_box` function had its own RFC and is tracked separately from the `test` feature at https://github.com/rust-lang/rust/issues/64102. Let's reflect this in the feature gate.
To avoid breaking all the benchmarks, libtest's `test::black_box` is a wrapping definition, not a reexport -- this means it is still under the `test` feature gate.
Cautiously add IntoIterator for arrays by value
Add the attribute described in #84133, `#[rustc_skip_array_during_method_dispatch]`, which effectively hides a trait from method dispatch when the receiver type is an array.
Then cherry-pick `IntoIterator for [T; N]` from #65819 and gate it with that attribute. Arrays can now be used as `IntoIterator` normally, but `array.into_iter()` has edition-dependent behavior, returning `slice::Iter` for 2015 and 2018 editions, or `array::IntoIter` for 2021 and later.
r? `@nikomatsakis`
cc `@LukasKalbertodt` `@rust-lang/libs`
Rework `init` and `cleanup`
This PR reworks the code in `std` that runs before and after `main` and centralizes this code respectively in the functions `init` and `cleanup` in both `sys_common` and `sys`. This makes is easy to see what code is executed during initialization and cleanup on each platform just by looking at e.g. `sys::windows::init`.
Full list of changes:
- new module `rt` in `sys_common` to contain `init` and `cleanup` and the runtime macros.
- `at_exit` and the mechanism to register exit handlers has been completely removed. In practice this was only used for closing sockets on windows and flushing stdout, which have been moved to `cleanup`.
- <s>On windows `alloc` and `net` initialization is now done in `init`, this saves a runtime check in every allocation and network use.</s>
further split up const_fn feature flag
This continues the work on splitting up `const_fn` into separate feature flags:
* `const_fn_trait_bound` for `const fn` with trait bounds
* `const_fn_unsize` for unsizing coercions in `const fn` (looks like only `dyn` unsizing is still guarded here)
I don't know if there are even any things left that `const_fn` guards... at least libcore and liballoc do not need it any more.
`@oli-obk` are you currently able to do reviews?
Explicitly implement `!Send` and `!Sync` for `sys::{Args, Env}`
Remove the field `_dont_send_or_sync_me: PhantomData<*mut ()>` in favor of an explicit implementation of `!Send` and `!Sync`.
Mention FusedIterator case in Iterator::fuse doc
Using `fuse` on an iterator that incorrectly implements
`FusedIterator` does not fuse the iterator. This commit adds a
note about this in the documentation of this method to increase
awareness about this potential issue (esp. when relying on fuse
in unsafe code).
Closes#83969
implement `TrustedRandomAccess` for `Take` iterator adapter
`TrustedRandomAccess` requires the iterator length to fit within `usize`. `take(n)` only constrains the upper bound of an iterator. So if the inner is `TrustedRandomAccess` (which already implies a finite length) then so can be `Take`.
```````@rustbot``````` label T-libs-impl
Move `sys_common::poison` to `sync::poison`
`sys_common` should not contain publicly exported types, only platform-independent abstractions on top of `sys`, which `sys_common::poison` is not. There is thus no reason for the module to not live under `sync`.
Part of #84187.
Remove duplicated fn(Box<[T]>) -> Vec<T>
`<[T]>::into_vec()` does the same thing as `Vec::from::<Box<[T]>>()`, so they can be implemented in terms of each other. This was the previous implementation of `Vec::from()`, but was changed in #78461. I'm not sure what the rationale was for that change, but it seems preferable to maintain a single implementation.
Improve `Iterator::by_ref` example
I split the example into two: one that fails to compile, and one that
works. I also made them identical except for the addition of `by_ref`
so we don't confuse readers with random differences.
cc `@steveklabnik,` who is the one that added the previous version of this example
Using `fuse` on an iterator that incorrectly implements
`FusedIterator` does not fuse the iterator. This commit adds a
note about this in the documentation of this method to increase
awareness about this potential issue (esp. when relying on fuse
in unsafe code).
Added CharIndices::offset function
The CharIndices iterator has a field internally called front_offset, that I think would be very useful to have access to.
You can already do something like ``char_indices.next().map(|(offset, _)| offset)``, but that is wordy, in addition to not handling the case where the iterator has ended, where you'd want the offset to be equal to the length.
I'm very new to the open source world and the rust repository, so I'm sorry if I missed a step or did something weird.
Improve rebuilding behaviour of BinaryHeap::retain.
This changes `BinaryHeap::retain` such that it doesn't always fully rebuild the heap, but only rebuilds the parts for which that's necessary.
This makes use of the fact that retain gives out `&T`s and not `&mut T`s.
Retaining every element or removing only elements at the end results in no rebuilding at all. Retaining most elements results in only reordering the elements that got moved (those after the first removed element), using the same logic as was already used for `append`.
cc `@KodrAus` `@sfackler` - We briefly discussed this possibility in the meeting last week while we talked about stabilization of this function (#71503).
Rollup of 7 pull requests
Successful merges:
- #84343 (Remove `ScopeTree::closure_tree`)
- #84376 (Uses flex to fix formatting of h1 at any width)
- #84377 (Followup to #83944)
- #84396 (Update LLVM submodule)
- #84402 (Move `sys_common::rwlock::StaticRWLock` etc. to `sys::unix::rwlock`)
- #84404 (Check for intrinsics before coercing to a function pointer)
- #84413 (Remove `sys::args::Args::inner_debug` and use `Debug` instead)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Remove `sys::args::Args::inner_debug` and use `Debug` instead
This removes the method `sys::args::Args::inner_debug` on all platforms and implements `Debug` for `Args` instead.
I believe this creates a more natural API for the different platforms under `sys`: export a type `Args: Debug + Iterator + ...` vs. `Args: Iterator + ...` and with a method `inner_debug`.
Move `sys_common::rwlock::StaticRWLock` etc. to `sys::unix::rwlock`
This moves `sys_common::rwlock::StaticRwLock`, `RWLockReadGuard` and `RWLockWriteGuard` to `sys::unix::rwlock`. They are already `#[cfg(unix)]` and don't need to be in `sys_common`.
Implement indexing slices with pairs of core::ops::Bound<usize>
Closes#49976.
I am not sure about code duplication between `check_range` and `into_maybe_range`. Should be former implemented in terms of the latter? Also this PR doesn't address code duplication between `impl SliceIndex for Range*`.
Format `Struct { .. }` on one line even with `{:#?}`.
The result of `debug_struct("A").finish_non_exhaustive()` before this change:
```
A {
..
}
```
And after this change:
```
A { .. }
```
If there's any fields, the result stays unchanged:
```
A {
field: value,
..
}
fix 'const-stable since' for NonZeroU*::new_unchecked
For the unsigned `NonZero` types, `new_unchecked` was const-stable from the start with https://github.com/rust-lang/rust/pull/50808. Fix the docs to accurately reflect that.
I think this `since` is also incorrect:
```rust
#[stable(feature = "from_nonzero", since = "1.31.0")]
impl From<$Ty> for $Int {
```
The signed nonzero types were only stabilized in 1.34, so that `From` impl certainly didn't exist before. But I had enough of digging through git histories after I figured out when `new_unchecked` became const-stable...^^
Replace `Void` in `sys` with never type
This PR replaces several occurrences in `sys` of the type `enum Void {}` with the Rust never type (`!`).
The name `Void` is unfortunate because in other languages (C etc.) it refers to a unit type, not an uninhabited type.
Note that the previous stabilization of the never type was reverted, however all uses here are implementation details and not publicly visible.
Move `sys::vxworks` code to `sys::unix`
Follow-up to #77666, `sys::vxworks` is almost identical to `sys::unix`, the only differences are the `rand`, `thread_local_dtor`, and `process` implementation. Since `vxworks` is `target_family = unix` anyway, there is no reason for the code not to live inside of `sys::unix` like all the other unix-OSes.
e41f378f82/compiler/rustc_target/src/spec/vxworks_base.rs (L12)
``@rustbot`` label: +T-libs-impl
Replace all `fmt.pad` with `debug_struct`
This replaces any occurrence of:
- `f.pad("X")` with `f.debug_struct("X").finish()`
- `f.pad("X { .. }")` with `f.debug_struct("X").finish_non_exhaustive()`
This is in line with existing formatting code such as
1255053067/library/std/src/sync/mpsc/mod.rs (L1470-L1475)
