static void SeenAt(EncounteredCollection info, Type type, MemberInfo m)
        {
            if (type == null)
            {
                return;
            }

            if (!info.Contains(type))
            {
                Console.WriteLine("# can't find referenced member: {0}; from: {1}", type, m);
                return;
            }

            info [type].At.Add(m);
        }