// 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. trait Foo { fn f(&self) -> isize; } trait Bar : Foo { fn g(&self) -> isize; } struct A { x: isize } impl Foo for A { fn f(&self) -> isize { 10 } } impl Bar for A { fn g(&self) -> isize { 20 } } // Call a function on Foo, given a T: Bar fn gg(a: &T) -> isize { a.f() } pub fn main() { let a = &A { x: 3 }; assert_eq!(gg(a), 10); }