src/test/run-pass/traits-multidispatch-infer-convert-target.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // Test that we can infer the Target based on the Self or vice versa.
  12
  13 // pretty-expanded FIXME #23616
  14
  15 use std::mem;
  16
  17 trait Convert<Target> {
  18     fn convert(&self) -> Target;
  19 }
  20
  21 impl Convert<u32> for i16 {
  22     fn convert(&self) -> u32 {
  23         *self as u32
  24     }
  25 }
  26
  27 impl Convert<i16> for u32 {
  28     fn convert(&self) -> i16 {
  29         *self as i16
  30     }
  31 }
  32
  33 fn test<T,U>(_: T, _: U, t_size: usize, u_size: usize)
  34 where T : Convert<U>
  35 {
  36     assert_eq!(mem::size_of::<T>(), t_size);
  37     assert_eq!(mem::size_of::<U>(), u_size);
  38 }
  39
  40 fn main() {
  41     use std::default::Default;
  42     // T = i16, U = u32
  43     test(22_i16, Default::default(),  2, 4);
  44
  45     // T = u32, U = i16
  46     test(22_u32, Default::default(), 4, 2);
  47 }