Tracking Issue for `lazy_cell_into_inner`

[tspiteri]

This superceded #109736 now that the lazy_cell feature has been stabilized.

Feature gate: #[feature(lazy_cell_into_inner)]

This is a tracking issue for LazyCell::into_inner and LazyLock::into_inner.

Public API

// core::cell (in core/src/cell/lazy.rs)

impl<T, F: FnOnce() -> T> LazyCell<T, F> {
    pub fn into_inner(this: Self) -> Result<T, F>;
}

// std::sync (in std/sync/lazy_lock.rs)

impl<T, F: FnOnce() -> T> LazyLock<T, F> {
    pub fn into_inner(this: Self) -> Result<T, F>;
}

Steps / History

• [x] Implementation: https://github.com/rust-lang/rust/pull/106152
• [ ] Final comment period (FCP)^1
• [ ] Stabilization PR

Unresolved Questions

• None yet.

[workingjubilee]

@tspiteri Would you be so kind as to make the tracking issue? (you could even just edit this one) We can edit it from there if we need to change things.

[tgross35]

Could this be renamed to lazy_cell_into_inner? I keep thinking this is is referencing an API that uses atomic consume operations, which was discussed for the implementation of OnceLock/LazyLock but ultimately rejected (e.g. here).

[workingjubilee]

Go for it.

[tgross35]

I was mostly asking for someone to rename the issue, but here we go https://github.com/rust-lang/rust/pull/127599. Rustbot has really been spot on picking reviewers for me recently.