Template argument (pointer to member function) initialization with NULL

["vagran.ast" <vagran.ast@xxxxxxxxx>]

Hi,

In the following code:

class A {
public:
    void SomeMethod() { }
};

template <class T, void (T::*SomeMethod)() = 0>
class B {

};

B<A> b1; // error: could not convert template argument '0' to 'void 
(A::*)()'

B<A, 0> b2; // error: could not convert template argument '0' to 'void 
(A::*)()'

void (A::*someMethod)() = 0; // OK

there are two compilation errors. AFAIK per C++ standard 0 is a valid 
value for a pointer to member
function. Variable of such type can be successfully initialized by 0 but 
template arguments can not.
Is it desired behavior or a bug?

gcc version 4.6.1