In file included from /usr/include/c++/4.6/utility:71:0,
                 from /usr/include/boost/config/no_tr1/utility.hpp:21,
                 from /usr/include/boost/config/select_stdlib_config.hpp:33,
                 from /usr/include/boost/config.hpp:40,
                 from /usr/include/boost/variant/detail/config.hpp:16,
                 from /usr/include/boost/variant/variant.hpp:23,
                 from /usr/include/boost/variant.hpp:17,
                 from recursive_variant.cpp:1:
/usr/include/c++/4.6/bits/stl_pair.h: In instantiation of 'std::pair<const float, boost::recursive_variant_>':
/usr/include/boost/variant/detail/visitation_impl.hpp:260:1:   instantiated from 'typename Visitor::result_type boost::detail::variant::visitation_impl(int, int, Visitor&, VoidPtrCV, mpl_::false_, NoBackupFlag, Which*, step0*) [with Which = mpl_::int_<0>, step0 = boost::detail::variant::visitation_impl_step<boost::mpl::l_iter<boost::mpl::l_item<mpl_::long_<2l>, int, boost::mpl::l_item<mpl_::long_<1l>, boost::recursive_wrapper<std::map<float, boost::variant<boost::detail::variant::recursive_flag<int>, std::map<float, boost::recursive_variant_>, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_>, std::less<float>, std::allocator<std::pair<const float, boost::variant<boost::detail::variant::recursive_flag<int>, std::map<float, boost::recursive_variant_>, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_> > > > >, boost::mpl::l_end> > >, boost::mpl::l_iter<boost::mpl::l_end> >, Visitor = boost::detail::variant::copy_into, VoidPtrCV = const void*, NoBackupFlag = boost::variant<boost::detail::variant::recursive_flag<int>, std::map<float, boost::recursive_variant_>, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_>::has_fallback_type_, typename Visitor::result_type = void, mpl_::false_ = mpl_::bool_<false>]'
/usr/include/boost/variant/variant.hpp:1776:13:   instantiated from 'static typename Visitor::result_type boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::copy_into, VoidPtrCV = const void*, T0_ = boost::detail::variant::recursive_flag<int>, T1 = std::map<float, boost::recursive_variant_>, T2 = boost::detail::variant::void_, T3 = boost::detail::variant::void_, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_, typename Visitor::result_type = void]'
/usr/include/boost/variant/variant.hpp:1798:13:   instantiated from 'typename Visitor::result_type boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor(Visitor&) const [with Visitor = boost::detail::variant::copy_into, T0_ = boost::detail::variant::recursive_flag<int>, T1 = std::map<float, boost::recursive_variant_>, T2 = boost::detail::variant::void_, T3 = boost::detail::variant::void_, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_, typename Visitor::result_type = void]'
/usr/include/boost/variant/variant.hpp:1425:9:   instantiated from 'boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::variant(const boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>&) [with T0_ = boost::detail::variant::recursive_flag<int>, T1 = std::map<float, boost::recursive_variant_>, T2 = boost::detail::variant::void_, T3 = boost::detail::variant::void_, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_, boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19> = boost::variant<boost::detail::variant::recursive_flag<int>, std::map<float, boost::recursive_variant_>, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_>]'
recursive_variant.cpp:11:17:   instantiated from here
/usr/include/c++/4.6/bits/stl_pair.h:93:11: error: 'std::pair<_T1, _T2>::second' has incomplete type
/usr/include/boost/variant/variant_fwd.hpp:232:12: error: forward declaration of 'struct boost::recursive_variant_'