[Boost-users] ambiguity between std::begin/end and boost::begin/end in gcc 4.6

Subject: [Boost-users] ambiguity between std::begin/end and boost::begin/end in gcc 4.6
From: Nathan Ridge (zeratul976_at_[hidden])
Date: 2010-12-26 23:25:38

The following code fails to compile with a development build of gcc 4.6:
 
#include <boost/range/adaptor/reversed.hpp>
#include <vector>
int main()
{
    std::vector<int> v;
    for (int i : v | boost::adaptors::reversed);
    return 0;
}

The errors are:
 
reversed.cpp: In function âint main()â:
reversed.cpp:16:39: error: call of overloaded âbegin(boost::range_detail::reverse_range<std::vector<int> >&)â is ambiguous
reversed.cpp:16:39: note: candidates are:
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/range_access.h:56:5: note: decltype (__cont->begin()) std::begin(const _Container&) [with _Container = boost::range_detail::reverse_range<std::vector<int> >, decltype (__cont->begin()) = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/range_access.h:46:5: note: decltype (__cont->begin()) std::begin(_Container&) [with _Container = boost::range_detail::reverse_range<std::vector<int> >, decltype (__cont->begin()) = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]
/home/nridge/lib/boost/boost/range/begin.hpp:107:61: note: typename boost::range_iterator<const T>::type boost::begin(const T&) [with T = boost::range_detail::reverse_range<std::vector<int> >, typename boost::range_iterator<const T>::type = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]
/home/nridge/lib/boost/boost/range/begin.hpp:96:55: note: typename boost::range_iterator<C>::type boost::begin(T&) [with T = boost::range_detail::reverse_range<std::vector<int> >, typename boost::range_iterator<C>::type = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]
reversed.cpp:16:39: error: call of overloaded âend(boost::range_detail::reverse_range<std::vector<int> >&)â is ambiguous
reversed.cpp:16:39: note: candidates are:
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/range_access.h:76:5: note: decltype (__cont->end()) std::end(const _Container&) [with _Container = boost::range_detail::reverse_range<std::vector<int> >, decltype (__cont->end()) = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/range_access.h:66:5: note: decltype (__cont->end()) std::end(_Container&) [with _Container = boost::range_detail::reverse_range<std::vector<int> >, decltype (__cont->end()) = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]
/home/nridge/lib/boost/boost/range/end.hpp:103:61: note: typename boost::range_iterator<const T>::type boost::end(const T&) [with T = boost::range_detail::reverse_range<std::vector<int> >, typename boost::range_iterator<const T>::type = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]
/home/nridge/lib/boost/boost/range/end.hpp:92:55: note: typename boost::range_iterator<C>::type boost::end(T&) [with T = boost::range_detail::reverse_range<std::vector<int> >, typename boost::range_iterator<C>::type = boost::reverse_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int> > >]

The problem is caused by an ambiguity between std::begin/end (new in C++0x) and boost::begin/end.
 
I've found this bug: https://svn.boost.org/trac/boost/ticket/4099
and this thread: http://groups.google.com/group/boost-devel-archive/browse_thread/thread/f97ab9c132ec590b/457aa0a5e165fab9?lnk=raot#457aa0a5e165fab9
 
which mention similar issues, but neither of them seem to address/fix the issue in Boost.Range.
 
Regards,
Nate.