This method hasn't really changed since is inception, and it can often be a
nice performance win for some situations. This method also imposes no burden on
implementors or users of `Clone` as it's just a default method on the side.
/// but can be overridden to reuse the resources of `a` to avoid unnecessary
/// allocations.
#[inline(always)]
- #[unstable(feature = "core",
- reason = "this function is rarely used")]
+ #[stable(feature = "rust1", since = "1.0.0")]
fn clone_from(&mut self, source: &Self) {
*self = source.clone()
}