diff --git a/source/mijin/util/traits.hpp b/source/mijin/util/traits.hpp
index 67426f9..5a8ce3d 100644
--- a/source/mijin/util/traits.hpp
+++ b/source/mijin/util/traits.hpp
@@ -300,6 +300,19 @@ static_assert(union_type<MyTemplate<int, int>, MyTemplate<double, double>, MyTem
 static_assert(!union_type<int*, int>);
 static_assert(union_type<int*, std::is_pointer<Type_>>);
 static_assert(!union_type<int, std::is_pointer<Type_>>);
+
+struct DetectNo {};
+struct DetectYes {
+    using some_type = double;
+};
+template<typename T>
+using detect_some_type = typename T::some_type;
+
+template<typename T>
+using some_type = detect_or_t<int, detect_some_type, T>;
+
+static_assert(std::is_same_v<some_type<DetectNo>, int>);
+static_assert(std::is_same_v<some_type<DetectYes>, double>);
 }
 #endif