Repository: rust
Issue: Tracking Issue for additional `array::IntoIter` constructors (feature `array_into_iter_constructors`)
Labels: T-libs-api,C-tracking-issue,A-array

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Feature gate: `#![feature(array_into_iter_constructors)]`

This is a tracking issue for the ~~`from_raw_parts`~~`new_unchecked` and `empty` constructors on `core::array::IntoIter`.

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This allows creating such an iterator with something other than a fully-initialized array.

### Public API

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```rust
// core::array

impl<T, const N: usize> IntoIter<T, N> {
    pub const fn empty() -> Self;
    pub const unsafe fn new_unchecked(buffer: [MaybeUninit<T>; N], initialized: Range<usize>) -> Self;
}
```

### Steps / History

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- [x] Implementation: https://github.com/rust-lang/rust/pull/91341
- [ ] Final comment period (FCP)
- [ ] Stabilization PR

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### Unresolved Questions

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- [ ] Should this be named `from_raw_parts` or something else?
- [ ] Should this have to go through an `ArrayVec`-like type (like how `Vec` has `from_raw_parts` instead of `vec::IntoIter` having it), instead of making the `IntoIter` directly?
- [ ] What's a good name for `new_unchecked`?  It was previously `from_raw_parts`, but was changed at reviewer request in the initial PR.  Then after that, `new` was deprecated, which makes me feel like `new_unchecked` is a bit odd too.
  - #93700 (temporarily) added a duplicate of this called `with_partial`, so that's another possible name.