Tracking Issue for `CovariantUnsafeCell`

Feature gate: #![feature(covariant_unsafe_cell)]

This is a tracking issue for https://github.com/rust-lang/libs-team/issues/815.

Public API

// core::cell

pub struct CovariantUnsafeCell<T: ?Sized> { ... }

impl<T> CovariantUnsafeCell<T> {
    pub const fn new(value: T) -> Self { ... }
    pub const fn into_inner(self) -> T { ... }
}

impl<T> CovariantUnsafeCell<T> {
    pub const fn get(&self) -> NonNull<T> { ... }
    pub const fn get_mut(&mut self) -> &mut T { ... }
    pub const fn raw_get(this: *const Self) -> *mut T { ... }
}

Steps / History

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

• ACP: https://github.com/rust-lang/libs-team/issues/815
• Implementation: https://github.com/rust-lang/rust/pull/159738
• Final comment period (FCP)^1
• Stabilization PR

Unresolved Questions

• What should be the return type of get? ACP originally proposed *mut T as with normal UnsafeCell, but the implementation PR used NonNull<T>