diff --git a/mcc/mcc_generics.h b/mcc/mcc_generics.h
index f4328ff..557e218 100644
--- a/mcc/mcc_generics.h
+++ b/mcc/mcc_generics.h
@@ -744,6 +744,13 @@ template <typename T>
 concept mcc_prohibited_zone_c =
     std::derived_from<T, mcc_pzone_interface_t<typename T::error_t>> && requires(const T t_const) {
         { t_const.name() } -> std::formattable<char>;
+
+        requires requires(typename T::pzone_policy_t pp) {
+            []() {
+                static constexpr auto v1 = T::pzone_policy_t::STOP_POLICY;
+                static constexpr auto v2 = T::pzone_policy_t::FLIP_POLICY;
+            }();
+        };
     };