#[unstable(feature = "new_uninit", issue = "63291")]
pub fn new_uninit_slice(len: usize) -> Rc<[mem::MaybeUninit<T>]> {
let data_layout = Layout::array::<mem::MaybeUninit<T>>(len).unwrap();
+ // This relies on `value` being the last field of `RcBox` in memory,
+ // so that the layout of `RcBox<T>` is the same as that of `RcBox<()>` followed by `T`.
let (layout, offset) = Layout::new::<RcBox<()>>().extend(data_layout).unwrap();
unsafe {
let allocated_ptr = Global.alloc(layout)
#[unstable(feature = "new_uninit", issue = "63291")]
pub fn new_uninit_slice(len: usize) -> Arc<[mem::MaybeUninit<T>]> {
let data_layout = Layout::array::<mem::MaybeUninit<T>>(len).unwrap();
+ // This relies on `value` being the last field of `RcBox` in memory,
+ // so that the layout of `RcBox<T>` is the same as that of `RcBox<()>` followed by `T`.
let (layout, offset) = Layout::new::<ArcInner<()>>().extend(data_layout).unwrap();
unsafe {
let allocated_ptr = Global.alloc(layout)