1 files changed, 18 insertions, 0 deletions

diff --git a/tests/ui/impl-trait/issues/issue-55872.rs b/tests/ui/impl-trait/issues/issue-55872.rs
new file mode 100644
index 00000000000..b76f8182b20
--- /dev/null
+++ b/tests/ui/impl-trait/issues/issue-55872.rs
@@ -0,0 +1,18 @@
+#![feature(impl_trait_in_assoc_type)]
+
+pub trait Bar {
+    type E: Copy;
+
+    fn foo<T>() -> Self::E;
+}
+
+impl<S> Bar for S {
+    type E = impl Copy;
+
+    fn foo<T>() -> Self::E {
+        //~^ ERROR type parameter `T` is part of concrete type but not used in parameter list for the `impl Trait` type alias
+        || ()
+    }
+}
+
+fn main() {}