src/test/run-pass/specialization/specialization-overlap-projection.rs

   1 // Copyright 2016 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 impls on projected self types can resolve overlap, even when the
  12 // projections involve specialization, so long as the associated type is
  13 // provided by the most specialized impl.
  14
  15 #![feature(specialization)]
  16
  17 trait Assoc {
  18     type Output;
  19 }
  20
  21 impl<T> Assoc for T {
  22     default type Output = bool;
  23 }
  24
  25 impl Assoc for u8 { type Output = u8; }
  26 impl Assoc for u16 { type Output = u16; }
  27
  28 trait Foo {}
  29 impl Foo for u32 {}
  30 impl Foo for <u8 as Assoc>::Output {}
  31 impl Foo for <u16 as Assoc>::Output {}
  32
  33 fn main() {}