1 files changed, 19 insertions, 0 deletions
diff --git a/src/test/ui/type-alias-impl-trait/generic_underconstrained2.rs b/src/test/ui/type-alias-impl-trait/generic_underconstrained2.rs
new file mode 100644
index 000000000..8adc0bf32
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/generic_underconstrained2.rs
@@ -0,0 +1,19 @@
+#![feature(type_alias_impl_trait)]
+
+fn main() {}
+
+type Underconstrained<T: std::fmt::Debug> = impl Send;
+
+// not a defining use, because it doesn't define *all* possible generics
+fn underconstrained<U>(_: U) -> Underconstrained<U> {
+    //~^ ERROR `U` doesn't implement `Debug`
+    5u32
+}
+
+type Underconstrained2<T: std::fmt::Debug> = impl Send;
+
+// not a defining use, because it doesn't define *all* possible generics
+fn underconstrained2<U, V>(_: U, _: V) -> Underconstrained2<V> {
+    //~^ ERROR `V` doesn't implement `Debug`
+    5u32
+}