diff --git a/core/function_traits.hh b/core/function_traits.hh
index b45b418c35..1d278a6207 100644
--- a/core/function_traits.hh
+++ b/core/function_traits.hh
@@ -31,6 +31,7 @@ struct function_traits<Ret(Args...)>
 {
     using return_type = Ret;
     using args_as_tuple = std::tuple<Args...>;
+    using signature = Ret (Args...);
  
     static constexpr std::size_t arity = sizeof...(Args);