1 files changed, 21 insertions, 0 deletions
diff --git a/src/test/ui/type-alias-impl-trait/issue-57700.rs b/src/test/ui/type-alias-impl-trait/issue-57700.rs
new file mode 100644
index 000000000..484589387
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/issue-57700.rs
@@ -0,0 +1,21 @@
+#![feature(arbitrary_self_types)]
+#![feature(type_alias_impl_trait)]
+
+use std::ops::Deref;
+
+trait Foo {
+    type Bar: Foo;
+
+    fn foo(self: impl Deref<Target = Self>) -> Self::Bar;
+}
+
+impl<C> Foo for C {
+    type Bar = impl Foo;
+
+    fn foo(self: impl Deref<Target = Self>) -> Self::Bar {
+        self
+        //~^ Error type parameter `impl Deref<Target = Self>` is part of concrete type but not used in parameter list for the `impl Trait` type alias
+    }
+}
+
+fn main() {}