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> {
    pub fn fill<'a>(this: &'a mut [MaybeUninit<T>], value: T) -> &'a mut [T]
    where
        T: Clone;

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

    pub fn fill_from<'a, I>(
        this: &'a mut [MaybeUninit<T>],
        it: I,
    ) -> (&'a mut [T], &'a mut [MaybeUninit<T>])
    where
        I: IntoIterator<Item = T>;
}

Steps / History

• Implementation: Implement MaybeUninit::fill{,_cloned,_mut,_with,_from} #117426, Implement MaybeUninit::fill{,_with,_from} #121280
• Make slice methods inherent: MaybeUninit inherent slice methods part 2 #135394
• 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).