Clion autocomplete does not work with forward declaration. Follow

I have a very simple project structure that has two class Big and Small in header file: big.h and small.h. Here are their code:

Big.h:

#include "small.h"

template<int N>
class Big {
public:
    int big_data;
    Big() {

    }
};

Small.h:

template<int N>
class Big;

template<int N>
class Big;

template<int N>
class Small {
public:
    int small_data;
    Small() {
    }
    void get_back_end_data(Big<N> *big) {

    }
};

Small has a function that take a Big object as an argument. The problem is that in the body of that function, autocomplete does not give me the public big_data.

If I directly include "big.h" inside small.h, it'd work. But my actual project requires predeclaring class Big inside small.h. There's no reason this shouldn't work, right?