diff --git a/src/test/run-pass/deriving-cmp-shortcircuit.rs b/src/test/run-pass/deriving-cmp-shortcircuit.rs new file mode 100644 index 00000000000..7f5c78cf602 --- /dev/null +++ b/src/test/run-pass/deriving-cmp-shortcircuit.rs @@ -0,0 +1,46 @@ +// 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 +} + +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); +}