Index: libcxx/test/std/containers/associative/map/map.cons/default_recursive.pass.cpp
===================================================================
--- libcxx/test/std/containers/associative/map/map.cons/default_recursive.pass.cpp
+++ libcxx/test/std/containers/associative/map/map.cons/default_recursive.pass.cpp
@@ -21,12 +21,11 @@
     std::map<int, X> m;
     std::map<int, X>::iterator i;
     std::map<int, X>::const_iterator ci;
+#if TEST_STD_VER <= 17
+    // These reverse_iterator specializations require X to be complete in C++20.
     std::map<int, X>::reverse_iterator ri;
     std::map<int, X>::const_reverse_iterator cri;
+#endif // TEST_STD_VER <= 17
 };
 
-int main(int, char**)
-{
-
-  return 0;
-}
+int main(int, char**) { return 0; }
Index: libcxx/test/std/containers/associative/multimap/multimap.cons/default_recursive.pass.cpp
===================================================================
--- libcxx/test/std/containers/associative/multimap/multimap.cons/default_recursive.pass.cpp
+++ libcxx/test/std/containers/associative/multimap/multimap.cons/default_recursive.pass.cpp
@@ -21,12 +21,11 @@
     std::multimap<int, X> m;
     std::multimap<int, X>::iterator i;
     std::multimap<int, X>::const_iterator ci;
+#if TEST_STD_VER <= 17
+    // These reverse_iterator specializations require X to be complete in C++20.
     std::multimap<int, X>::reverse_iterator ri;
     std::multimap<int, X>::const_reverse_iterator cri;
+#endif // TEST_STD_VER <= 17
 };
 
-int main(int, char**)
-{
-
-  return 0;
-}
+int main(int, char**) { return 0; }