[Bug libstdc++/49058] [C++0x] Bind no-arguments functor failed using std::bind with -pedantic option.

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49058

--- Comment #13 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-05-22 
22:17:10 UTC ---
What about creating an artificially dependent context, thus amenable to SFINAE,
like:

// Call as const
template<typename... _Args, typename _Result
  = decltype( std::declval<typename conditional<(sizeof...(_Args) >= 0),
    typename add_const<_Functor>::type,
typename add_const<_Functor>::type>::type>()

(
              _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
                                  std::declval<tuple<_Args...>&>() )... ) )>
        _Result