[boost] uncreatable

From: Jason Hise (chaos_at_[hidden])
Date: 2005-09-25 19:49:33

Why does the following compile?  The parameter type of A's pure virtual 
function is private.  How come B can see it, allowing it to override the 
pure virtual function?

class A
{
private:
    struct S {  };
    virtual void bar ( S ) = 0;
};

class B : public A
{
public:
    virtual void bar ( A::S )
    {
    }
};

int main (  )
{
    B b;
    return 0;
}

-Jason