diff --git a/include/asio/detail/work_dispatcher.hpp b/include/asio/detail/work_dispatcher.hpp
index 4e1baa068d..9e7a33e0a1 100644
--- a/include/asio/detail/work_dispatcher.hpp
+++ b/include/asio/detail/work_dispatcher.hpp
@@ -40,8 +40,13 @@ struct empty_work_function
   }
 };
 
-template <typename Function>
+template <typename Function, typename = void>
 struct work_result
+{
+};
+
+template <typename Function>
+struct work_result<Function, void_t<result_of_t<decay_t<Function>()>>>
 {
   typedef decay_t<result_of_t<decay_t<Function>()>> type;
 };