This allows the use of `NonZero<Unique<T>>` for owned,
non-null raw pointers.
cc https://github.com/Gankro/collect-rs/pull/103
//! Exposes the NonZero lang item which provides optimization hints.
use ops::Deref;
+use ptr::Unique;
/// Unsafe trait to indicate what types are usable with the NonZero struct
pub unsafe trait Zeroable {}
unsafe impl<T> Zeroable for *const T {}
unsafe impl<T> Zeroable for *mut T {}
+unsafe impl<T> Zeroable for Unique<T> { }
unsafe impl Zeroable for int {}
unsafe impl Zeroable for uint {}
unsafe impl Zeroable for i8 {}