// Copyright 2013 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. // check that the derived impls for the comparison traits shortcircuit // where possible, by having a type that fails when compared as the // second element, so this passes iff the instances shortcircuit. pub struct FailCmp; impl Eq for FailCmp { fn eq(&self, _: &FailCmp) -> bool { fail!("eq") } } impl Ord for FailCmp { fn lt(&self, _: &FailCmp) -> bool { fail!("lt") } } impl TotalEq for FailCmp { fn equals(&self, _: &FailCmp) -> bool { fail!("equals") } } impl TotalOrd for FailCmp { fn cmp(&self, _: &FailCmp) -> Ordering { fail!("cmp") } } #[deriving(Eq,Ord,TotalEq,TotalOrd)] struct ShortCircuit { x: int, y: FailCmp } pub fn main() { let a = ShortCircuit { x: 1, y: FailCmp }; let b = ShortCircuit { x: 2, y: FailCmp }; assert!(a != b); assert!(a < b); assert!(!a.equals(&b)); assert_eq!(a.cmp(&b), ::std::cmp::Less); }