Re: ambiguous constructor? Is it right?

Dear all,

I have the following problem, that I'll try to explain with a very
minimal example:

class A
{
};

class B
{
public:
    B() { }
    B(const A&) { }
    B(const B&) { }
};

class C
{
public:
    operator A() const { return A(); }
    operator B() const { return B(); }
};

int main(){
    const C& c = C();
    B b = static_cast<B>(c);
    return 0;
}

Basically, I would expect that casting a const C& to B would call the
operator B() of C and that the construction C -> B (through the copy

constructor) would be preferred to C -> A -> B. In Visual C++ 9 it
actually does so, but gcc complains that there is an ambiguity. Who's
right (I guess Visual c++) and, in case, how could I nicely work around
the problem?