diff --git a/libs/util/include/psemek/util/at.hpp b/libs/util/include/psemek/util/at.hpp
index fcfb4496..a69f7b89 100644
--- a/libs/util/include/psemek/util/at.hpp
+++ b/libs/util/include/psemek/util/at.hpp
@@ -60,7 +60,16 @@ namespace psemek::util
 	}
 
 	template <typename T, typename Key>
-	auto & at(std::vector<T> && container, Key const & key)
+	auto & at(std::vector<T> & container, Key const & key)
+	{
+		if (key < container.size())
+			return container[key];
+
+		throw key_error<Key>(key);
+	}
+
+	template <typename T, typename Key>
+	auto & at(std::vector<T> const & container, Key const & key)
 	{
 		if (key < container.size())
 			return container[key];