diff --git a/source/mijin/util/traits.hpp b/source/mijin/util/traits.hpp
index 78d8011..e96452f 100644
--- a/source/mijin/util/traits.hpp
+++ b/source/mijin/util/traits.hpp
@@ -112,6 +112,15 @@ struct is_type_member<TElement, TCollection<Ts...>>
 template<typename TElement, typename TCollection>
 constexpr bool is_type_member_v = is_type_member<TElement, TCollection>::value;
 
+template<typename TFrom, typename TTo>
+using copy_const_t = std::conditional_t<std::is_const_v<TFrom>, std::add_const_t<TTo>, std::remove_const_t<TTo>>;
+
+template<typename TFrom, typename TTo>
+using copy_volatile_t = std::conditional_t<std::is_volatile_v<TFrom>, std::add_volatile_t<TTo>, std::remove_volatile_t<TTo>>;
+
+template<typename TFrom, typename TTo>
+using copy_cv_t = copy_const_t<TFrom, copy_volatile_t<TFrom, TTo>>;
+
 //
 // public functions
 //