back(pop_back(array)) doesn't work

[Mathias Gaunard]

The following code does not work as expected:

#include <boost/fusion/include/pop_back.hpp>
#include <boost/fusion/include/back.hpp>
#include <boost/fusion/include/array.hpp>
#include <iostream>

int main()
{
    boost::array<std::size_t, 2> a = { 10, 50 };
    std::cout << boost::fusion::back(boost::fusion::pop_back(a)) << std::endl;
}

The program displays 50 instead of 10.