Re: conversion to non-scalar type error in inheritance hierarchy

I am working on container class with different implementations
and want to add stl-style iterators. Now, I am confronted with
a "conversion to non-scalar type" error which I do not
understand. Any comments are appreciated. Many thanks in
advance!

The interface for the different implementations is defined in
the base class A. A1 is one implementation. B is the iterator
base class and C its implementation in A1. I really do not see
a problem since C inherits from B but the compiler says:

test.cpp: In function =91int main()':
test.cpp:34: error: conversion from =91A<int>::B' to non-scalar type
=91A1<int>::C' requested

Code:
template <class X>
class A
{
        public:
                class B
                {
                        public:
                                virtual ~B () {}
                                virtual void method () {}
                };
                virtual ~A () {}
                virtual B begin ()=0;
};

template <class X>
class A1 : public A<X>
{
        public:
                class C : public A<X>::B
                {
                        public:
                                ~C () {}
                                void method ( ) {}
                };
                ~A1 () {}
                typename A<X>::B begin ( )
                {
                        C test;
                        return test;
                }
};

int main ( )
{
        A1<int> test;
        A1<int>::C test_it = test.begin ();

        return 0;
}