Feature gate: #![feature(maybe_uninit_fill)]

This is a tracking issue for ACP rust-lang/libs-team#156

Public API

// core::mem

impl<T> [MaybeUninit<T>] {
    // formerly `fill`
    pub fn write_filled<'a>(this: &'a mut [MaybeUninit<T>], value: T) -> &'a mut [T]
        where T: Clone

    // formerly `fill_with`
    pub fn write_with<'a, F>(this: &'a mut [MaybeUninit<T>], f: F) -> &'a mut [T]
        where F: FnMut() -> T;

    // formerly `fill_from`
    pub fn write_iter<'a, I>(this: &'a mut [MaybeUninit<T>], iter: I) -> (&'a mut [T], &'a mut [MaybeUninit<T>])
        where I: Iterator<Item = T>;
}

Steps / History

• Implementation: Implement MaybeUninit::fill{,_cloned,_mut,_with,_from} #117426
• Make slice methods inherent: Add inherent versions of MaybeUninit methods for slices #129259
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• Naming: these were originally named fill, fill_with, and fill_from to be consistent consistent with slice::{fill_with,fill_from}. Since changing to slice-inherent methods, these needed to be renamed to avoid conflict. Should we change to naming that keeps fill? Amanieu suggested fill_init at Add inherent versions of MaybeUninit methods for slices #129259 (comment).