Tracking Issue for adding `partial_sort_unstable` to `[T]`

Feature gate: #![feature(slice_partial_sort_unstable)]

This is a tracking issue for https://github.com/rust-lang/libs-team/issues/685.

Public API

impl<T> [T] {
  pub fn partial_sort_unstable<R>(&mut self, range: R) where T: Ord, R: RangeBounds<usize> { ... }
  pub fn partial_sort_unstable_by<F, R>(&mut self, range: R, mut compare: F) where F: FnMut(&T, &T) -> Ordering, R: RangeBounds<usize> { ... }
  pub fn partial_sort_unstable_by_key<K, F, R>(&mut self, range: R, mut f: F) where F: FnMut(&T) -> K, K: Ord, R: RangeBounds<usize>  { ... }
}

#[test]
fn demostration() {
    let mut before: Vec<u32> = vec![4, 4, 3, 3, 1, 1, 2, 2];
    let last = 6;
    let mut d = before.clone();
    d.sort();

    before.partial_sort_unstable_by(..last, |a, b| a.cmp(b));
    assert_eq!(&d[0..last], &before[0..last]);
}

Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

• ACP: https://github.com/rust-lang/libs-team/issues/685
• Implementation: https://github.com/rust-lang/rust/pull/149318
• Final comment period (FCP)^1
• Stabilization PR

Unresolved Questions

• None yet.

Start with the feature gate slice_partial_sort_unstable and the checked implementation PR #149318, then review ACP #685 and the linked stabilization guide. The remaining work is to follow the tracking checklist through final comment period and stabilization; the issue is already under way rather than an unclaimed implementation task.