1 files changed, 37 insertions, 0 deletions
diff --git a/tests/ui/deriving/deriving-cmp-shortcircuit.rs b/tests/ui/deriving/deriving-cmp-shortcircuit.rs
new file mode 100644
index 000000000..140373e95
--- /dev/null
+++ b/tests/ui/deriving/deriving-cmp-shortcircuit.rs
@@ -0,0 +1,37 @@
+// run-pass
+// check that the derived impls for the comparison traits shortcircuit
+// where possible, by having a type that panics when compared as the
+// second element, so this passes iff the instances shortcircuit.
+
+
+use std::cmp::Ordering;
+
+pub struct FailCmp;
+impl PartialEq for FailCmp {
+    fn eq(&self, _: &FailCmp) -> bool { panic!("eq") }
+}
+
+impl PartialOrd for FailCmp {
+    fn partial_cmp(&self, _: &FailCmp) -> Option<Ordering> { panic!("partial_cmp") }
+}
+
+impl Eq for FailCmp {}
+
+impl Ord for FailCmp {
+    fn cmp(&self, _: &FailCmp) -> Ordering { panic!("cmp") }
+}
+
+#[derive(PartialEq,PartialOrd,Eq,Ord)]
+struct ShortCircuit {
+    x: isize,
+    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_eq!(a.cmp(&b), ::std::cmp::Ordering::Less);
+}