library/core/tests/pin.rs

   1 use core::pin::Pin;
   2
   3 #[test]
   4 fn pin_const() {
   5     // test that the methods of `Pin` are usable in a const context
   6
   7     const POINTER: &'static usize = &2;
   8
   9     const PINNED: Pin<&'static usize> = Pin::new(POINTER);
  10     const PINNED_UNCHECKED: Pin<&'static usize> = unsafe { Pin::new_unchecked(POINTER) };
  11     assert_eq!(PINNED_UNCHECKED, PINNED);
  12
  13     const INNER: &'static usize = Pin::into_inner(PINNED);
  14     assert_eq!(INNER, POINTER);
  15
  16     const INNER_UNCHECKED: &'static usize = unsafe { Pin::into_inner_unchecked(PINNED) };
  17     assert_eq!(INNER_UNCHECKED, POINTER);
  18
  19     const REF: &'static usize = PINNED.get_ref();
  20     assert_eq!(REF, POINTER);
  21
  22     // Note: `pin_mut_const` tests that the methods of `Pin<&mut T>` are usable in a const context.
  23     // A const fn is used because `&mut` is not (yet) usable in constants.
  24     const fn pin_mut_const() {
  25         let _ = Pin::new(&mut 2).into_ref();
  26         let _ = Pin::new(&mut 2).get_mut();
  27         let _ = unsafe { Pin::new(&mut 2).get_unchecked_mut() };
  28     }
  29
  30     pin_mut_const();
  31 }