diff --git a/include/ylt/struct_pack/reflection.hpp b/include/ylt/struct_pack/reflection.hpp
index cd3fad0279..d8e1e0f99d 100644
--- a/include/ylt/struct_pack/reflection.hpp
+++ b/include/ylt/struct_pack/reflection.hpp
@@ -201,7 +201,7 @@ struct has_user_defined_id_ADL_impl : std::false_type {};
 
 template <typename T>
 struct has_user_defined_id_ADL_impl<
-    T, std::void_t<decltype(constant_checker<struct_pack_id((T*)nullptr)>)>>
+    T, std::void_t<constant_checker<struct_pack_id((T*)nullptr)>>>
     : std::true_type {};
 
 template <typename T>