Tracking Issue for MaybeUninit methods for arrays · Issue #96097 · rust-lang/rust (original) (raw)

This is a meta-tracking issue for multiple APIs that are linked across multiple issues. Right now it only includes two methods, but since there seems to be a desire to add more, this issue can be used as a placeholder for those discussions until those methods are added.

Public API

impl MaybeUninit { pub const fn array_assume_init(array: [Self; N]) -> [T; N]; }

impl<T, const N: usize> MaybeUninit<[T; N]> { pub const fn transpose(self) -> [MaybeUninit; N]; }

impl<T, const N: usize> [MaybeUninit; N] { pub const fn transpose(self) -> MaybeUninit<[T; N]>; }

Steps / History

• Add MaybeUninit methods uninit_array, slice_get_ref, slice_get_mut #65580
• Add MaybeUninit method array_assume_init #80600
• Make const: MaybeUninit array cleanup #96099
• Add MaybeUninit array transpose impls #102023
• Replace uses of MaybeUninit::uninit_array() with inline const blocks. #125082
• Final comment period (FCP)
• Stabilization PR

Relevant Links

• Old tracking issue for array_assume_init: Tracking Issue for maybe_uninit_array_assume_init #80908

Unresolved Questions

• Should MaybeUninit::uninit_array::<LEN>() be stabilised if it can be replaced by [const { MaybeUninit::uninit() }; LEN] ?
  • No, fcp close to remove that: Tracking Issue for MaybeUninit methods for arrays #96097 (comment)
• What other APIs should be added for arrays?
• Is array_assume_init the right pattern, or should we convert from [MaybeUninit<T>, N] back to MaybeUninit<[T; N]> first?