[Bug c++/44908] New: SFINAE vs pointer to member via virtual base

[paolo dot carlini at oracle dot com]

This is another case where we have a compile-time errors (Ok with ICC). Note,
with swapped From and To types compiles.

struct A { };

struct E
: virtual A { };

template<bool, typename T = void> struct enable_if { typedef T type; };
template<typename T> struct enable_if<false, T> { };

template<typename From, typename To>
  class mini_is_convertible
  {
    typedef char one;
    typedef struct { char arr[2]; } two;

    template<typename To1>
      static void test_aux(To1);

    template<typename From1, typename To1>
      // static decltype(test_aux<To1>(std::declval<From1>()), one())
      static typename
      enable_if<(sizeof(test_aux<To1>(From1()), 1) > 0), one>::type
      test(int);

    template<typename, typename>
      static two test(...);

    public:
      static const bool value = sizeof(test<From, To>(0)) == 1;
  }; 

int main()
{
  mini_is_convertible<int (E::*) (int), int (A::*) (int)>::value; // compiles
  mini_is_convertible<int (E::*), int (A::*)>::value;             // compiles 
  mini_is_convertible<int (A::*) (int), int (E::*) (int)>::value; // doesn't
  mini_is_convertible<int (A::*), int (E::*)>::value;             // doesn't
}


-- 
           Summary: SFINAE vs pointer to member via virtual base
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: paolo dot carlini at oracle dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44908