src/test/run-pass/supertrait-default-generics.rs

   1 // Copyright 2012 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 // There is some other borrowck bug, so we make the stuff not mut.
  12
  13 use std::ops::Add;
  14
  15 trait Positioned<S> {
  16   fn SetX(&mut self, S);
  17   fn X(&self) -> S;
  18 }
  19
  20 trait Movable<S: Add<Output=S>>: Positioned<S> {
  21   fn translate(&mut self, dx: S) {
  22     let x = self.X() + dx;
  23     self.SetX(x);
  24   }
  25 }
  26
  27 struct Point<S> { x: S, y: S }
  28
  29 impl<S: Clone> Positioned<S> for Point<S> {
  30     fn SetX(&mut self, x: S) {
  31         self.x = x;
  32     }
  33     fn X(&self) -> S {
  34         self.x.clone()
  35     }
  36 }
  37
  38 impl<S: Clone + Add<Output=S>> Movable<S> for Point<S> {}
  39
  40 pub fn main() {
  41     let mut p = Point{ x: 1, y: 2};
  42     p.translate(3);
  43     assert_eq!(p.X(), 4);
  44 }