1 files changed, 45 insertions, 0 deletions
diff --git a/src/test/ui/associated-types/associated-types-projection-in-supertrait.rs b/src/test/ui/associated-types/associated-types-projection-in-supertrait.rs
new file mode 100644
index 000000000..ead405fcf
--- /dev/null
+++ b/src/test/ui/associated-types/associated-types-projection-in-supertrait.rs
@@ -0,0 +1,45 @@
+// run-pass
+#![allow(dead_code)]
+// Test that we are handle to correctly handle a projection type
+// that appears in a supertrait bound. Issue #20559.
+
+
+trait A
+{
+    type TA;
+
+    fn dummy(&self) { }
+}
+
+trait B<TB>
+{
+    fn foo (&self, t : TB) -> String;
+}
+
+trait C<TC : A> : B<<TC as A>::TA> { }
+
+struct X;
+
+impl A for X
+{
+    type TA = i32;
+}
+
+struct Y;
+
+impl C<X> for Y { }
+
+// Both of these impls are required for successful compilation
+impl B<i32> for Y
+{
+    fn foo (&self, t : i32) -> String
+    {
+        format!("First {}", t)
+    }
+}
+
+fn main ()
+{
+    let y = Y;
+    assert_eq!(y.foo(5), format!("First 5"));
+}