message: Fix compile on GCC 4.8
  relates
diff: @@ -139,7 +139,9 @@ public:
  detail::pseudo_tuple
  >::type;
  + trivial_match_case(trivial_match_case&&) = default;
  trivial_match_case(const trivial_match_case&) = default;
  + trivial_match_case& operator=(trivial_match_case&&) = default;
  trivial_match_case& operator=(const trivial_match_case&) = default;
  trivial_match_case(F f)
  