http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45942
--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> 2010-10-09
18:07:42 UTC ---
(In reply to comment #13)
> The reason that I did not succeed in making ClassB a friend of ClassA is that
> C++ is not very logical.
Maybe so, but that's not a bug in GCC.
The next version of C++ is more lenient in what is allowed in a friend
declaration and I think it is possible to declare a typedef as a friend so you
could create a class template with a nested member and declare that member as a
friend. That template could be specialized to make certain specializations of
classB a friend:
template<class T, int C, class AA>
struct Befriender {
typedef int type;
};
template<class T, int C>
struct Befriender<T, C, A<T,C>> {
typedef B<T,C,A<T,C>&> type;
};
template<class T, int C>
class A {
friend typename Befriender<T,C,A>::type;
};
I *think* this would work, when Befriender::type results in "friend int" it is
ignored, without error.
