This is a distilled form of the problem Vladimir found in http://tinyurl.com/3zsha The attached snippet fails with the latest CVS image in GCC 3.2 (see err.out). If I comment the first line #include <boost/bind/arg.hpp> // comment to get it working the snippet works OK. Also, the code works fine for Boost 1.31, (by previously replacing reverse_iter_fold with iter_fold_backward, of course) regardless of wether I comment or not the first line. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo foo.cpp: In instantiation of `f1::apply<mpl_::_2, mpl_::_1>': /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/bind.hpp:205: instantiated from `boost::mpl::apply_wrap2<f1, mpl_::_2, mpl_::_1>' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/bind.hpp:205: instantiated from `boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>::apply<int, boost::mpl::v_iter<f3, 3>, mpl_::na, mpl_::na, mpl_::na>' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:140: instantiated from `boost::mpl::apply_wrap2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:140: instantiated from `boost::mpl::apply2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:140: instantiated from `boost::mpl::aux::reverse_iter_fold_impl<4, boost::mpl::v_iter<f3, 0>, boost::mpl::v_iter<f3, 4>, int, boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, boost::mpl::protect<mpl_::arg<1>, 0> >' /usr/local/boost_1_32_alpha/boost/mpl/reverse_iter_fold.hpp:43: instantiated from `boost::mpl::reverse_iter_fold<f3, int, f2, boost::arg<1> >' foo.cpp:23: instantiated from here foo.cpp:11: no type named `type' in `struct mpl_::_2' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/bind.hpp: In instantiation of `boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>::apply<int, boost::mpl::v_iter<f3, 3>, mpl_::na, mpl_::na, mpl_::na>': /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:140: instantiated from `boost::mpl::apply_wrap2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:140: instantiated from `boost::mpl::apply2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:140: instantiated from `boost::mpl::aux::reverse_iter_fold_impl<4, boost::mpl::v_iter<f3, 0>, boost::mpl::v_iter<f3, 4>, int, boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, boost::mpl::protect<mpl_::arg<1>, 0> >' /usr/local/boost_1_32_alpha/boost/mpl/reverse_iter_fold.hpp:43: instantiated from `boost::mpl::reverse_iter_fold<f3, int, f2, boost::arg<1> >' foo.cpp:23: instantiated from here /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/bind.hpp:205: no type named `type' in `struct boost::mpl::apply_wrap2<f1, mpl_::_2, mpl_::_1> ' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp: In instantiation of `boost::mpl::aux::reverse_iter_fold_impl<4, boost::mpl::v_iter<f3, 0>, boost::mpl::v_iter<f3, 4>, int, boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, boost::mpl::protect<mpl_::arg<1>, 0> >': /usr/local/boost_1_32_alpha/boost/mpl/reverse_iter_fold.hpp:43: instantiated from `boost::mpl::reverse_iter_fold<f3, int, f2, boost::arg<1> >' foo.cpp:23: instantiated from here /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:140: no type named `type' in `struct boost::mpl::apply2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:141: no type named `type' in `struct boost::mpl::apply2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:142: no type named `type' in `struct boost::mpl::apply2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:143: no type named `type' in `struct boost::mpl::apply2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/aux_/preprocessed/gcc/reverse_iter_fold_impl.hpp:146: no type named `type' in `struct boost::mpl::apply2<boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, int, boost::mpl::v_iter<f3, 3> >' /usr/local/boost_1_32_alpha/boost/mpl/reverse_iter_fold.hpp: In instantiation of `boost::mpl::reverse_iter_fold<f3, int, f2, boost::arg<1> >': foo.cpp:23: instantiated from here /usr/local/boost_1_32_alpha/boost/mpl/reverse_iter_fold.hpp:43: no type named ` state' in `struct boost::mpl::aux::reverse_iter_fold_impl<4, boost::mpl::v_iter<f3, 0>, boost::mpl::v_iter<f3, 4>, int, boost::mpl::bind2<f1, mpl_::_2, mpl_::_1>, boost::mpl::protect<mpl_::arg<1>, 0> >' foo.cpp:23: syntax error before `;' token foo.cpp: In function `int main()': foo.cpp:27: `f4' undeclared (first use this function) foo.cpp:27: (Each undeclared identifier is reported only once for each function it appears in.) foo.cpp:27: parse error before `;' token