forall(T &)
struct A {
    T * next;
};

struct B {
    A(B) link;
};

int main(void) {
	B end = { { 0p } };
	B two = { { &end } };
	B one = { { &two } };
	B * head = &one;

	for (B ** it = &head ; (*it)->link.next ; it = &(*it)->link.next) {
		printf("loop\n");
	}
	printf("done\n");
}