rust/library/alloc/tests
bors 8a7ca936e6 Auto merge of #105587 - tgross35:once-cell-min, r=m-ou-se
Partial stabilization of `once_cell`

This PR aims to stabilize a portion of the `once_cell` feature:

- `core::cell::OnceCell`
- `std::cell::OnceCell` (re-export of the above)
- `std::sync::OnceLock`

This will leave `LazyCell` and `LazyLock` unstabilized, which have been moved to the `lazy_cell` feature flag.

Tracking issue: https://github.com/rust-lang/rust/issues/74465 (does not fully close, but it may make sense to move to a new issue)

Future steps for separate PRs:
- ~~Add `#[inline]` to many methods~~ #105651
- Update cranelift usage of the `once_cell` crate
- Update rust-analyzer usage of the `once_cell` crate
- Update error messages discussing once_cell

## To be stabilized API summary

```rust
// core::cell (in core/cell/once.rs)

pub struct OnceCell<T> { .. }

impl<T> OnceCell<T> {
    pub const fn new() -> OnceCell<T>;
    pub fn get(&self) -> Option<&T>;
    pub fn get_mut(&mut self) -> Option<&mut T>;
    pub fn set(&self, value: T) -> Result<(), T>;
    pub fn get_or_init<F>(&self, f: F) -> &T where F: FnOnce() -> T;
    pub fn into_inner(self) -> Option<T>;
    pub fn take(&mut self) -> Option<T>;
}

impl<T: Clone> Clone for OnceCell<T>;
impl<T: Debug> Debug for OnceCell<T>
impl<T> Default for OnceCell<T>;
impl<T> From<T> for OnceCell<T>;
impl<T: PartialEq> PartialEq for OnceCell<T>;
impl<T: Eq> Eq for OnceCell<T>;
```

```rust
// std::sync (in std/sync/once_lock.rs)

impl<T> OnceLock<T> {
    pub const fn new() -> OnceLock<T>;
    pub fn get(&self) -> Option<&T>;
    pub fn get_mut(&mut self) -> Option<&mut T>;
    pub fn set(&self, value: T) -> Result<(), T>;
    pub fn get_or_init<F>(&self, f: F) -> &T where F: FnOnce() -> T;
    pub fn into_inner(self) -> Option<T>;
    pub fn take(&mut self) -> Option<T>;
}

impl<T: Clone> Clone for OnceLock<T>;
impl<T: Debug> Debug for OnceLock<T>;
impl<T> Default for OnceLock<T>;
impl<#[may_dangle] T> Drop for OnceLock<T>;
impl<T> From<T> for OnceLock<T>;
impl<T: PartialEq> PartialEq for OnceLock<T>
impl<T: Eq> Eq for OnceLock<T>;
impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceLock<T>;
unsafe impl<T: Send> Send for OnceLock<T>;
unsafe impl<T: Sync + Send> Sync for OnceLock<T>;
impl<T: UnwindSafe> UnwindSafe for OnceLock<T>;
```

No longer planned as part of this PR, and moved to the `rust_cell_try` feature gate:

```rust
impl<T> OnceCell<T> {
    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E> where F: FnOnce() -> Result<T, E>;
}

impl<T> OnceLock<T> {
    pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E> where F: FnOnce() -> Result<T, E>;
}
```

I am new to this process so would appreciate mentorship wherever needed.
2023-03-30 10:12:23 +00:00
..
arc.rs Remove Vec/Rc storage reuse opt 2022-11-18 10:39:50 +00:00
autotraits.rs Replace libstd, libcore, liballoc in line comments. 2022-12-30 14:00:42 +01:00
borrow.rs Move various ui const tests to library 2020-09-04 02:35:27 +02:00
boxed.rs Remove ~const from alloc 2023-03-28 10:37:16 -07:00
btree_set_hash.rs Include the length in BTree hashes 2021-10-01 12:29:09 -07:00
c_str.rs Remove use of reverted std::ffi::c_char 2022-04-27 14:01:04 -07:00
const_fns.rs impl const Default for Box<[T]> and Box<str> 2022-04-11 12:14:18 -07:00
cow_str.rs mv std libs to library/ 2020-07-27 19:51:13 -05:00
fmt.rs enable fuzzy_provenance_casts lint in liballoc 2022-11-20 19:12:18 +01:00
heap.rs Rename AllocRef to Allocator and (de)alloc to (de)allocate 2020-12-04 14:47:15 +01:00
lib.rs Auto merge of #105587 - tgross35:once-cell-min, r=m-ou-se 2023-03-30 10:12:23 +00:00
linked_list.rs Classify BinaryHeap & LinkedList unit tests as such 2022-03-11 11:33:59 +01:00
rc.rs Remove Vec/Rc storage reuse opt 2022-11-18 10:39:50 +00:00
slice.rs Update rand in the stdlib tests, and remove the getrandom feature from it 2023-01-04 14:52:41 -08:00
str.rs Rollup merge of #100311 - xfix:lines-fix-handling-of-bare-cr, r=ChrisDenton 2023-03-23 00:00:30 +05:30
string.rs Adjust tests for isize::MAX allocation always being checked 2022-03-25 00:57:05 -05:00
thin_box.rs Make use of pointer::is_aligned[_to] 2022-08-21 15:46:03 +04:00
vec_deque.rs fix advance_by impl for vec_deque and add tests 2023-03-27 16:03:30 +02:00
vec.rs replace advance_by returning usize with Result<(), NonZeroUsize> 2023-03-27 16:03:14 +02:00