Feature gate: #![feature(arc_unwrap_or_clone)]

This is a tracking issue for arc_unwrap_or_clone. This feature adds methods to Rc/Arc to gain access to the contained value, by unwrapping if there is exactly one reference, or cloning otherwise. It is equivalent to cloning the inner value, but saves the clone operation if the caller has the only reference to the rc'd value.

Public API

impl<T: Clone> Arc<T> {
    pub fn unwrap_or_clone(this: Self) -> T;
}

Steps / History

• Implementation: impl Arc::unwrap_or_clone #91589
• Final comment period (FCP)
• Stabilization PR

Unresolved Questions

• More bikeshedding on the name is possible. Existing discussion on irlo. There seems to be consensus that the current name is good.