1 files changed, 18 insertions, 0 deletions
diff --git a/src/test/ui/lint/dead-code/impl-trait.rs b/src/test/ui/lint/dead-code/impl-trait.rs
new file mode 100644
index 000000000..757b8f83e
--- /dev/null
+++ b/src/test/ui/lint/dead-code/impl-trait.rs
@@ -0,0 +1,18 @@
+#![deny(dead_code)]
+
+trait Trait {
+    type Type;
+}
+
+impl Trait for () {
+    type Type = ();
+}
+
+type Used = ();
+type Unused = (); //~ ERROR type alias `Unused` is never used
+
+fn foo() -> impl Trait<Type = Used> {}
+
+fn main() {
+    foo();
+}