Feature gate: #![feature(clone_from_ref)]
This is a tracking issue for Box::clone_from_ref, Arc::clone_from_ref, and Rc::clone_from_ref. try_* and *_in functions are under this tracking issue as well as allocator_api.
Allows creating a Box<T>/Rc<T>/Arc<T> by cloning from a &T where T: CloneToUninit. Notably, these work even when T is unsized (e.g. a slice).
Public API
// alloc::boxed impl<T: ?Sized + CloneToUninit> Box<T> { pub fn clone_from_ref(val: &T) -> Box<T>; // also under feature(allocator_api) pub fn try_clone_from_ref(val: &T) -> Result<Box<T>, AllocError>; } impl<T: ?Sized + CloneToUninit, A: Allocator> Box<T, A> { // also under feature(allocator_api) pub fn clone_from_ref_in(val: &T, alloc: A) -> Box<T, A>; // also under feature(allocator_api) pub fn try_clone_from_ref_in(val: &T, alloc: A) -> Result<Box<T, A>, AllocError>; } // alloc::rc impl<T: ?Sized + CloneToUninit> Rc<T> { pub fn clone_from_ref(val: &T) -> Rc<T>; // also under feature(allocator_api) pub fn try_clone_from_ref(val: &T) -> Result<Rc<T>, AllocError>; } impl<T: ?Sized + CloneToUninit, A: Allocator> Rc<T, A> { // also under feature(allocator_api) pub fn clone_from_ref_in(val: &T, alloc: A) -> Rc<T, A>; // also under feature(allocator_api) pub fn try_clone_from_ref_in(val: &T, alloc: A) -> Result<Rc<T, A>, AllocError>; } // alloc::sync impl<T: ?Sized + CloneToUninit> Arc<T> { pub fn clone_from_ref(val: &T) -> Arc<T>; // also under feature(allocator_api) pub fn try_clone_from_ref(val: &T) -> Result<Arc<T>, AllocError>; } impl<T: ?Sized + CloneToUninit, A: Allocator> Arc<T, A> { // also under feature(allocator_api) pub fn clone_from_ref_in(val: &T, alloc: A) -> Arc<T, A>; // also under feature(allocator_api) pub fn try_clone_from_ref_in(val: &T, alloc: A) -> Result<Arc<T, A>, AllocError>; }
Steps / History
(Remember to update the S-tracking-* label when checking boxes.)
- ACP:
Box::new_from_reffor making aBox<T>from a&TwhereT: CloneToUninit + ?Sized(andRcandArc) libs-team#483 - Implementation: Add
Box::clone_from_refand similar underfeature(clone_from_ref)#149079 - Final comment period (FCP)1
- Stabilization PR
Unresolved Questions
- None yet.