Tracking Issue for `slice_shift` (`shift_left`/`shift_right`)

Feature gate: #![feature(slice_shift)]

This is a tracking issue for the [T]::shift_left and [T]::shift_right methods, which are the safe versions of memmove.

Public API

// in core
impl<T> [T] {
    pub fn shift_left<const N: usize>(&mut self, inserted: [T; N]) -> [T; N];
    pub fn shift_right<const N: usize>(&mut self, inserted: [T; N]) -> [T; N];
}

Steps / History

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

• ACP: https://github.com/rust-lang/libs-team/issues/717
• Implementation: #151812
• Final comment period (FCP)^1
• Stabilization PR

Unresolved Questions

• "Our conclusion from the meeting was: if it's possible to do this without appreciable runtime performance impact, we'd love to avoid a panic. If doing this would add runtime performance impact, we're happy to ship the panicking version." ~ https://github.com/rust-lang/libs-team/issues/717#issuecomment-3807205664

Start with the public API in core and the implementation referenced as #151812, then review the linked stabilization guidance and the unresolved-question discussion. Done means completing the final comment period and stabilization PR for slice_shift, rather than adding the initial implementation.