diff --git a/source/mijin/util/traits.hpp b/source/mijin/util/traits.hpp
index dfe4303..78d8011 100644
--- a/source/mijin/util/traits.hpp
+++ b/source/mijin/util/traits.hpp
@@ -39,8 +39,6 @@ struct always_false_val
 template<auto V>
 inline constexpr bool always_false_val_v = always_false_val<V>::value;
 
-
-
 template<template<typename> typename TFilter, typename... TArgs>
 struct TypeFilter;
 
@@ -103,6 +101,17 @@ struct is_any_type : std::disjunction<std::is_same<T, Types>...> {};
 template<typename T, typename... Types>
 static constexpr bool is_any_type_v = is_any_type<T, Types...>::value;
 
+template<typename TElement, typename TCollection>
+struct is_type_member;
+
+template<typename TElement, template<typename...> typename TCollection, typename... Ts>
+struct is_type_member<TElement, TCollection<Ts...>>
+  : std::bool_constant<(... || std::is_same<TElement, Ts>{})>
+{};
+
+template<typename TElement, typename TCollection>
+constexpr bool is_type_member_v = is_type_member<TElement, TCollection>::value;
+
 //
 // public functions
 //