diff --git a/include/nlohmann/detail/json_custom_base_class.hpp b/include/nlohmann/detail/json_custom_base_class.hpp
index 3d13903d9..0f1fbfd1f 100644
--- a/include/nlohmann/detail/json_custom_base_class.hpp
+++ b/include/nlohmann/detail/json_custom_base_class.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <type_traits>
+#include <type_traits> // conditional, is_same
 
 namespace nlohmann
 {