1 files changed, 22 insertions, 0 deletions
diff --git a/tests/ui/coherence/coherence-rfc447-constrained.rs b/tests/ui/coherence/coherence-rfc447-constrained.rs
new file mode 100644
index 000000000..9d1d86883
--- /dev/null
+++ b/tests/ui/coherence/coherence-rfc447-constrained.rs
@@ -0,0 +1,22 @@
+// run-pass
+// check that trait matching can handle impls whose types are only
+// constrained by a projection.
+
+trait IsU32 {}
+impl IsU32 for u32 {}
+
+trait Mirror { type Image: ?Sized; }
+impl<T: ?Sized> Mirror for T { type Image = T; }
+
+trait Bar {}
+impl<U: Mirror, V: Mirror<Image=L>, L: Mirror<Image=U>> Bar for V
+    where U::Image: IsU32 {}
+
+trait Foo { fn name() -> &'static str; }
+impl Foo for u64 { fn name() -> &'static str { "u64" } }
+impl<T: Bar> Foo for T { fn name() -> &'static str { "Bar" }}
+
+fn main() {
+    assert_eq!(<u64 as Foo>::name(), "u64");
+    assert_eq!(<u32 as Foo>::name(), "Bar");
+}