// 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>;
}