#include <iostream>

#include <boost/fusion/include/io.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/fusion/include/boost_tuple.hpp>
#include <boost/fusion/include/join.hpp>
#include <boost/fusion/include/vector.hpp>

int main() {

    boost::tuple<int> a;
    boost::tuple<double> b;

    // OK
    std::cout << boost::fusion::join(a,b) << std::endl;

    boost::fusion::vector<> c;
    boost::fusion::vector<double> d;

    // OK
    std::cout << boost::fusion::join(c,d) << std::endl;

    boost::tuple<> e;
    boost::tuple<double> f;

    // compiler error
    std::cout << boost::fusion::join(e,f) << std::endl;

}