55cae0a094
I ended up altering the semantics of Json's PartialOrd implementation. It used to be the case that Null < Null, but I can't think of any reason for an ordering other than the default one so I just switched it over to using the derived implementation. This also fixes broken `PartialOrd` implementations for `Vec` and `TreeMap`. RFC: 0028-partial-cmp
44 lines
1.3 KiB
Rust
44 lines
1.3 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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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 fails when compared as the
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// second element, so this passes iff the instances shortcircuit.
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pub struct FailCmp;
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impl PartialEq for FailCmp {
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fn eq(&self, _: &FailCmp) -> bool { fail!("eq") }
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}
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impl PartialOrd for FailCmp {
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fn partial_cmp(&self, _: &FailCmp) -> Option<Ordering> { fail!("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 { fail!("cmp") }
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}
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#[deriving(PartialEq,PartialOrd,Eq,Ord)]
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struct ShortCircuit {
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x: int,
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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::Less);
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}
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