diff --git a/libs/util/include/psemek/util/hash_table.hpp b/libs/util/include/psemek/util/hash_table.hpp
index dc3d77e8..b35cf3ee 100644
--- a/libs/util/include/psemek/util/hash_table.hpp
+++ b/libs/util/include/psemek/util/hash_table.hpp
@@ -296,6 +296,11 @@ namespace psemek::util
 			{
 				return static_cast<Hash const &>(*this)(pair.first);
 			}
+
+			std::size_t operator()(std::pair<Key, Value> const & pair) const
+			{
+				return static_cast<Hash const &>(*this)(pair.first);
+			}
 		};
 
 		template <typename Key, typename Value, typename Equal>
@@ -320,6 +325,11 @@ namespace psemek::util
 			{
 				return static_cast<Equal const &>(*this)(pair1.first, pair2.first);
 			}
+
+			bool operator()(std::pair<Key, Value> const & pair1, std::pair<Key const, Value> const & pair2) const
+			{
+				return static_cast<Equal const &>(*this)(pair1.first, pair2.first);
+			}
 		};
 
 	}