`try_reserve` and `try_reserve_exact` docs refer to calling `reserve` and `reserve_exact`.
`try_reserve_exact` example uses `try_reserve` method instead of `try_reserve_exact`.
Make `cow_is_borrowed` methods const
Constify the following methods of `alloc::borrow::Cow`:
- `is_borrowed`
- `is_owned`
Analogous to the const methods `is_some` and `is_none` for Option, and `is_ok` and `is_err` for Result.
These methods are still unstable under `cow_is_borrowed`.
Possible because of #49146 (Allow if and match in constants).
Tracking issue: #65143
Constify the following methods of `alloc::borrow::Cow`:
- `is_borrowed`
- `is_owned`
These methods are still unstable under `cow_is_borrowed`.
Possible because of #49146 (Allow if and match in constants).
Tracking issue: #65143
Shorten liballoc doc intra link while readable
r? @jyn514
Do you want to reviews these sort of pull requests in the future? I might send a few of them while reading vec code.
Report an ambiguity if both modules and primitives are in scope for intra-doc links
Closes https://github.com/rust-lang/rust/issues/75381
- Add a new `prim@` disambiguator, since both modules and primitives are in the same namespace
- Refactor `report_ambiguity` into a closure
Additionally, I noticed that rustdoc would previously allow `[struct@char]` if `char` resolved to a primitive (not if it had a DefId). I fixed that and added a test case.
I also need to update libstd to use `prim@char` instead of `type@char`. If possible I would also like to refactor `ambiguity_error` to use `Disambiguator` instead of its own hand-rolled match - that ran into issues with `prim@` (I updated one and not the other) and it would be better for them to be in sync.
stabilize ptr_offset_from
This stabilizes ptr::offset_from, and closes https://github.com/rust-lang/rust/issues/41079. It also removes the deprecated `wrapping_offset_from`. This function was deprecated 19 days ago and was never stable; given an FCP of 10 days and some waiting time until FCP starts, that leaves at least a month between deprecation and removal which I think is fine for a nightly-only API.
Regarding the open questions in https://github.com/rust-lang/rust/issues/41079:
* Should offset_from abort instead of panic on ZSTs? -- As far as I know, there is no precedent for such aborts. We could, however, declare this UB. Given that the size is always known statically and the check thus rather cheap, UB seems excessive.
* Should there be more methods like this with different restrictions (to allow nuw/nsw, perhaps) or that return usize (like how isize-taking offset is more conveniently done with usize-taking add these days)? -- No reason to block stabilization on that, we can always add such methods later.
Also nominating the lang team because this exposes an intrinsic.
The stabilized method is best described [by its doc-comment](56d4b2d69a/src/libcore/ptr/const_ptr.rs (L227)). The documentation forgot to mention the requirement that both pointers must "have the same provenance", aka "be derived from pointers to the same allocation", which I am adding in this PR. This is a precondition that [Miri already implements](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=a3b9d0a07a01321f5202cd99e9613480) and that, should LLVM ever obtain a `psub` operation to subtract pointers, will likely be required for that operation (following the semantics in [this paper](https://people.mpi-sws.org/~jung/twinsem/twinsem.pdf)).
New zeroed slice
Add to #63291 the methods
```rust
impl<T> Box<[T]> { pub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>]> {…} }
impl<T> Rc<[T]> { pub fn new_zeroed_slice(len: usize) -> Rc<[MaybeUninit<T>]> {…} }
impl<T> Arc<[T]> { pub fn new_zeroed_slice(len: usize) -> Arc<[MaybeUninit<T>]> {…} }
```
as suggested in https://github.com/rust-lang/rust/issues/63291#issuecomment-605511675 .
Also optimize `{Rc, Arc}::new_zeroed` to use `alloc_zeroed`, otherwise they are no more efficient than using `new_uninit` and zeroing the memory manually (which was the original implementation).
Move to intra-doc links for task.rs and vec.rs
Partial fix for #75080
links for [`get`], [`get_mut`] skipped due to #75643
link for [`copy_from_slice`] skipped due to #63351
Don't panic in Vec::shrink_to_fit
We can help the compiler see that `Vec::shrink_to_fit` will never reach the panic case in `RawVec::shrink_to_fit`, just by guarding the call only for cases where the capacity is strictly greater. A capacity less than the length is only possible through an unsafe call to `set_len`, which would break the `Vec` invariants, so `shrink_to_fit` can just ignore that.
This removes the panicking code from the examples in both #71861 and #75636.
