Geometry Boost List: [ggl] Surprising ADL

Subject: [ggl] Surprising ADL
From: feverzsj
Date: 2010-05-05 08:55:58

hi,
    The following code won't compile on msvc8/9, and both of the 
compliers give the same diagnostic output for "ambiguous call to 
overloaded function" and "one of the overloads is found by ADL".

#include <boost/geometry/geometry.hpp>

namespace ns
{

template<typename T1, typename T2, typename T3>
bool transform(T1 const& a, T2& b, T3 const& c)
{
    return boost::geometry::transform(a, b, c);
}

template<typename T1, typename T2>
bool transform(T1 const& a, T2& b)
{
    return boost::geometry::transform(a, b);
}

}

int main()
{
    using namespace ns;

    typedef boost::geometry::point_xy<double> point2d;

    point2d        pt1, pt2;

    transform(pt1, pt2);
//    ns::transform(pt1, pt2); // with qualified call, everything is ok
}

I think that's mainly because of the unqualified call inside 
boost::geometry::transform().

template <typename Geometry1, typename Geometry2>
inline bool transform(Geometry1 const& geometry1, Geometry2& geometry2)
{
    concept::check<Geometry1 const>();
    concept::check<Geometry2>();

    typename detail::transform::select_strategy<Geometry1, 
Geometry2>::type strategy;
    return transform(geometry1, geometry2, strategy);  // unqualified call.
}

Regards, ZhouShuangJiang