tests/ui/traits/multidispatch-infer-convert-target.rs

   1 // run-pass
   2 // Test that we can infer the Target based on the Self or vice versa.
   3
   4
   5 use std::mem;
   6
   7 trait Convert<Target> {
   8     fn convert(&self) -> Target;
   9 }
  10
  11 impl Convert<u32> for i16 {
  12     fn convert(&self) -> u32 {
  13         *self as u32
  14     }
  15 }
  16
  17 impl Convert<i16> for u32 {
  18     fn convert(&self) -> i16 {
  19         *self as i16
  20     }
  21 }
  22
  23 fn test<T,U>(_: T, _: U, t_size: usize, u_size: usize)
  24 where T : Convert<U>
  25 {
  26     assert_eq!(mem::size_of::<T>(), t_size);
  27     assert_eq!(mem::size_of::<U>(), u_size);
  28 }
  29
  30 fn main() {
  31     // T = i16, U = u32
  32     test(22_i16, Default::default(),  2, 4);
  33
  34     // T = u32, U = i16
  35     test(22_u32, Default::default(), 4, 2);
  36 }