mirror of https://github.com/rust-lang/rust
38 lines
884 B
Rust
38 lines
884 B
Rust
//@ run-pass
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// check that the derived impls for the comparison traits shortcircuit
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// where possible, by having a type that panics when compared as the
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// second element, so this passes iff the instances shortcircuit.
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use std::cmp::Ordering;
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pub struct FailCmp;
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impl PartialEq for FailCmp {
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fn eq(&self, _: &FailCmp) -> bool { panic!("eq") }
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}
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impl PartialOrd for FailCmp {
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fn partial_cmp(&self, _: &FailCmp) -> Option<Ordering> { panic!("partial_cmp") }
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}
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impl Eq for FailCmp {}
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impl Ord for FailCmp {
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fn cmp(&self, _: &FailCmp) -> Ordering { panic!("cmp") }
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}
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#[derive(PartialEq,PartialOrd,Eq,Ord)]
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struct ShortCircuit {
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x: isize,
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y: FailCmp
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}
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pub fn main() {
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let a = ShortCircuit { x: 1, y: FailCmp };
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let b = ShortCircuit { x: 2, y: FailCmp };
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assert!(a != b);
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assert!(a < b);
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assert_eq!(a.cmp(&b), ::std::cmp::Ordering::Less);
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}
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