Here is a contrived example that illustrates the issue: #include <boost/bind.hpp> #include <boost/ref.hpp> #include <string> // Define a simple class for our example class Crayon { public: explicit Crayon(const std::string &color=std::string()):m_color(color) {} const std::string &GetColor() const {return m_color;} private: std::string m_color; }; int main(int argc, char *argv[]) { using namespace std; using namespace boost; Crayon cr("blue"); boost::reference_wrapper<const Crayon> crefCr(cr); // This compiles std::string color(boost::bind(&Crayon::GetColor,_1)(cr)); // This also compiles, using an explicit get on crefCr std::string colorFromConstRef(boost::bind(&Crayon::GetColor,boost::bind(&boost::referenc e_wrapper<const Crayon>::get,_1))(crefCr)); // This doesn't compile, however, even though the reference_wrapper class template has // an overloaded operator T& () const function std::string colorFromConstRef2(boost::bind(&Crayon::GetColor,_1)(crefCr)); }