1 files changed, 22 insertions, 0 deletions
diff --git a/tests/ui/regions/resolve-re-error-ice.rs b/tests/ui/regions/resolve-re-error-ice.rs
new file mode 100644
index 000000000..f37b27a82
--- /dev/null
+++ b/tests/ui/regions/resolve-re-error-ice.rs
@@ -0,0 +1,22 @@
+// check-pass
+
+// Allow this for now, can remove this UI test when this becomes a hard error.
+#![allow(implied_bounds_entailment)]
+
+use std::collections::hash_map::{Keys, HashMap};
+use std::marker::PhantomData;
+
+trait MapAssertion<'a, K, V, R> {
+    fn key_set(&self) -> Subject<Keys<K, V>, (), R>;
+}
+
+struct Subject<'a, T, V, R>(PhantomData<(&'a T, V, R)>);
+
+impl<'a, K, V, R> MapAssertion<'a, K, V, R> for Subject<'a, HashMap<K, V>, (), R>
+{
+    fn key_set(&self) -> Subject<'a, Keys<K, V>, (), R> {
+        todo!()
+    }
+}
+
+fn main() {}