template<typename T>
void hash_queue(queue<size_t>& q){
  q.push( typeid(T).hash_code() );
}

template<typename T, typename... Ts>
void hash_queue(queue<size_t>& q){
  hash_queue<Ts...>(q);
  q.push( typeid(T).hash_code() );
}

int main(){
  queue<size_t> q;
  hash_queue<int, float, double>(q);
  return 0;
}

main.cpp: In instantiation of ‘void hash_queue(std::queue<long unsigned int>&) [with T = float; Ts = {double}]’:
main.cpp:19:22:   required from ‘void hash_queue(std::queue<long unsigned int>&) [with T = int; Ts = {float, double}]’
main.cpp:25:35:   required from here
main.cpp:19:22: error: call of overloaded ‘hash_queue(std::queue<long unsigned int>&)’ is ambiguous
   hash_queue<Ts...>(q);
                      ^
main.cpp:19:22: note: candidates are:
main.cpp:13:6: note: void hash_queue(std::queue<long unsigned int>&) [with T = double]
 void hash_queue(queue<size_t>& q){
      ^
main.cpp:18:6: note: void hash_queue(std::queue<long unsigned int>&) [with T = double; Ts = {}]
 void hash_queue(queue<size_t>& q){