#include <boost/fusion/include/pair.hpp>
#include <boost/fusion/include/std_tuple.hpp>

#include <tuple>
#include <iostream>

int main(){

	struct NotDefaultConstructible {
		NotDefaultConstructible(int){};
	};

	// prints 0
	std::cout << std::is_default_constructible< NotDefaultConstructible >::value << std::endl;

	using fusion_pair1 = boost::fusion::pair<int, NotDefaultConstructible>;

	// should print 0
	// fails to compile on clang (xcode 7, 3.4, 3.6, 3.7), gcc 4.9
	// prints 1 on gcc 5, clang 3.4
	std::cout << std::is_default_constructible< fusion_pair1 >::value << std::endl;

	return 0;
}