// Copyright 2012 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. // There is some other borrowck bug, so we make the stuff not mut. use std::ops::Add; trait Positioned { fn SetX(&mut self, _: S); fn X(&self) -> S; } trait Movable>: Positioned { fn translate(&mut self, dx: S) { let x = self.X() + dx; self.SetX(x); } } struct Point { x: S, y: S } impl Positioned for Point { fn SetX(&mut self, x: S) { self.x = x; } fn X(&self) -> S { self.x.clone() } } impl> Movable for Point {} pub fn main() { let mut p = Point{ x: 1, y: 2}; p.translate(3); assert_eq!(p.X(), 4); }