1 files changed, 36 insertions, 0 deletions
diff --git a/tests/ui/type-alias-impl-trait/higher_kinded_params3.rs b/tests/ui/type-alias-impl-trait/higher_kinded_params3.rs
new file mode 100644
index 000000000..6edfccaf7
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/higher_kinded_params3.rs
@@ -0,0 +1,36 @@
+//! This test checks that we can't actually have an opaque type behind
+//! a binder that references variables from that binder.
+
+// edition: 2021
+
+#![feature(type_alias_impl_trait)]
+
+trait B {
+    type C;
+}
+
+struct A;
+
+impl<'a> B for &'a A {
+    type C = Tait<'a>;
+}
+
+type Tait<'a> = impl std::fmt::Debug + 'a;
+
+struct Terminator;
+
+type Successors<'a> = impl std::fmt::Debug + 'a;
+
+impl Terminator {
+    fn successors(&self, mut f: for<'x> fn(&'x ()) -> <&'x A as B>::C) -> Successors<'_> {
+        f = g;
+        //~^ ERROR mismatched types
+        //~| ERROR item constrains opaque type that is not in its signature
+    }
+}
+
+fn g(x: &()) -> &() {
+    x
+}
+
+fn main() {}