Inner struct accessing host member

[Philippe Sigaud via Digitalmars-d-learn]

I'd have thought that this would work:

struct A
{
    int[] i;
    B b;

    struct B
    {
        void foo() { i ~= 1;}
    }
}

void main()
{
    A a;
    a.b.foo();
}

But the compiler tells me 'need this for i of type int[]'.
Is there any way I can gain access on i inside B?