Question

The following code has no problems in gcc. in VS 2010 express it fails giving

------ Build started: Project: helium, Configuration: Debug Win32 ------
  testvs.cpp
..\..\helium\src\legacy\testvs.cpp(21): error C2664: 'ulink' : cannot convert parameter 1 from 'VP<T>' to 'VP<T> &'
          with
          [
              T=F
          ]
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

In it the same for any visual studio version or is it a problem limited to vs 2010?
The problem disappears if the second operator() definition is removed

template<typename T> struct S{
    void operator()(T&){}
    void operator()(){}
};



  template <typename T,typename G=typename T::GP,void (S<T>::*f)(T&) =&S<T>::operator() > struct VP{
 void fa(){}
 };


template<typename T> void ulink( VP<T >& v){}



  struct F{
    typedef int GP;
  };

   void f(){

     VP<F> vps;
     ulink(vps);
   }

Answer 1

Thanks to Seth Carnegie for confirming that this is yet another VS unsolved bug.

Possible workarounds

1) include in another structure

template<typename L> struct Con{
     L& l;
     Con(L& pl):l(pl){}
};

template<typename T> void ulink(const Con<VP<T > >& v){
v.l.fa();
}

2) keep the template more generic

template<typename T> void gulink(T& v){
v.fa();
}