1 files changed, 20 insertions, 0 deletions
diff --git a/src/test/ui/type-alias-impl-trait/generic_duplicate_param_use5.rs b/src/test/ui/type-alias-impl-trait/generic_duplicate_param_use5.rs
new file mode 100644
index 000000000..3bd1dda63
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/generic_duplicate_param_use5.rs
@@ -0,0 +1,20 @@
+#![feature(type_alias_impl_trait)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+// test that unused generic parameters are ok
+type Two<T, U> = impl Debug;
+
+fn two<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+    (t, u)
+    //~^ ERROR `T` doesn't implement `Debug`
+    //~| ERROR `U` doesn't implement `Debug`
+}
+
+fn three<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+    (u, t)
+    //~^ ERROR `T` doesn't implement `Debug`
+    //~| ERROR `U` doesn't implement `Debug`
+}