id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
7503,for_each does not compile with g++-4.7.1,veso <vveesskkoo@…>,Joel de Guzman,"Hello,

The following code works fine with g++-4.4 and can not compile with g++-4.7.1.

#include    <iostream>
#include    <string>
#include    <type_traits>
#include    <typeinfo>

#include    <boost/fusion/include/map.hpp>
#include    <boost/fusion/include/filter_if.hpp>
#include    <boost/fusion/include/for_each.hpp>

namespace fusion = boost::fusion;

template<typename Key_Base_T, typename Pair_T>
struct is_same_key: public std::is_same<Key_Base_T, typename Pair_T::first_type> {};

struct print_ftor {
    template<typename Key_T, typename Value_T>
    inline void
    operator()(const boost::fusion::pair<Key_T, Value_T>& pair) const {
        std::cout << ""type: "" << typeid(Key_T).name() << "", value: "" << pair.second << std::endl;
    }
};

int main () {

    typedef fusion::map<    fusion::pair<int, char>,
                            fusion::pair<double, std::string>   >
            map_type;

    map_type map_sequence(  fusion::make_pair<int>('X'),
                            fusion::make_pair<double>(""Men"")    );

    fusion::for_each(   fusion::filter_if< is_same_key< double, boost::mpl::_1> >(map_sequence),
                        print_ftor());

    return 0;
}


The error which the compiler produces is:

g++-4.7 -o test -std=c++0x -Wall -pedantic  -I/home/veso/boost_1_52_0_beta1  main.c++
main.c++: In instantiation of ‘struct is_same_key<double, mpl_::arg<1> >’:
/home/veso/boost_1_52_0_beta1/boost/fusion/algorithm/iteration/detail/for_each.hpp:32:9:   required from ‘void boost::fusion::detail::for_each_linear(const First&, const Last&, const F&, mpl_::false_) [with First = boost::fusion::filter_iterator<boost::mpl::inherit2<boost::fusion::forward_traversal_tag, boost::fusion::associative_tag>, boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >::category, const boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >, 0>, boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >::category, const boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >, 2>, is_same_key<double, mpl_::arg<1> > >; Last = boost::fusion::filter_iterator<boost::mpl::inherit2<boost::fusion::forward_traversal_tag, boost::fusion::associative_tag>, boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >::category, const boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >, 2>, boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >::category, const boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >, 2>, is_same_key<double, mpl_::arg<1> > >; F = print_ftor; mpl_::false_ = mpl_::bool_<false>]’
/home/veso/boost_1_52_0_beta1/boost/fusion/algorithm/iteration/detail/for_each.hpp:42:9:   required from ‘void boost::fusion::detail::for_each_dispatch(Sequence&, const F&, Tag) [with Sequence = const boost::fusion::filter_view<const boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >, is_same_key<double, mpl_::arg<1> > >; F = print_ftor; Tag = boost::mpl::inherit2<boost::fusion::forward_traversal_tag, boost::fusion::associative_tag>]’
/home/veso/boost_1_52_0_beta1/boost/fusion/algorithm/iteration/detail/for_each.hpp:132:9:   required from ‘void boost::fusion::detail::for_each(Sequence&, const F&, mpl_::false_) [with Sequence = const boost::fusion::filter_view<const boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >, is_same_key<double, mpl_::arg<1> > >; F = print_ftor; mpl_::false_ = mpl_::bool_<false>]’
/home/veso/boost_1_52_0_beta1/boost/fusion/algorithm/iteration/for_each.hpp:49:9:   required from ‘typename boost::enable_if<boost::fusion::traits::is_sequence<Sequence>, void>::type boost::fusion::for_each(const Sequence&, const F&) [with Sequence = boost::fusion::filter_view<const boost::fusion::map<boost::fusion::pair<int, char>, boost::fusion::pair<double, std::basic_string<char> > >, is_same_key<double, mpl_::arg<1> > >; F = print_ftor; typename boost::enable_if<boost::fusion::traits::is_sequence<Sequence>, void>::type = void]’
main.c++:33:19:   required from here
main.c++:13:8: error: no type named ‘first_type’ in ‘struct mpl_::arg<1>’
make: *** [all] Error 1


For the test I used Debian stable with g++-4.7 installed from the backport repository.

The bug appears with boost versions 1.42, 1.51, 1.51beta1

",Bugs,closed,Boost 1.52.0,fusion,Boost 1.51.0,Problem,fixed,,