Android 10  |  10.0.0_r6
C++程序  |  22行  |  175 B 

class X
{
  friend class A;
};


template <typename T1, typename T2>
class B
{
};

template <class T>
struct C
{
};

class D
{
    B<D, class A> x;
    friend struct C<A>;
};