| //! Intrinsics that cannot be moved to `core` because they depend on `alloc` types. |
| #![unstable(feature = "liballoc_internals", issue = "none")] |
| |
| use core::mem::MaybeUninit; |
| |
| use crate::boxed::Box; |
| |
| /// Writes `x` into `b`. |
| /// |
| /// This is needed for `vec!`, which can't afford any extra copies of the argument (or else debug |
| /// builds regress), has to be written fully as a call chain without `let` (or else this breaks inference |
| /// of e.g. unsizing coercions), and can't use an `unsafe` block as that would then also |
| /// include the user-provided `$x`. |
| #[rustc_intrinsic] |
| pub fn write_box_via_move<T>(b: Box<MaybeUninit<T>>, x: T) -> Box<MaybeUninit<T>>; |
