我有一个文件input_service.h和一个文件instances.h，在instances.h中我有一个宏Extends_Instance，当我在instances.h中使用该宏时，它工作正常，但当我在input_service.h中使用它时，它导致<error-type>。
input_service.h：

#pragma once

#include <placeholder/instances/instances.h>
#include <placeholder/ff.h>

typedef enum e_keyState {
    KS_NOT_PRESSED   = 0b00000000,
    KS_JUST_PRESSED  = 0b00000010,
    KS_JUST_RELEASED = 0b00000100, 
    KS_HELD          = 0b00000010
} e_keyState;

// % (KeyDown, KeyPressed, KeyReleased, KeyUp) -> `@property InputService->m_getKeyState`

typedef struct InputService {
    Extends_Instance;  // !!!!!! ERROR HERE !!!!!! 
    // Extends_Instance -> <error-type>
    // 

    // & `(e_keyState & KS_DOWN) == 0` -> Key is being held
    // => `(e_keyState & KS_RELEASED) == 0` -> Key was just released
    // => ... see `@enum e_keyState`
    public method(m_getKeyState, e_keyState)(struct InputService *self, char key_code);
    internal method(m_frameBegun, void)(struct InputService *self);
    
    internal readOnly ALLEGRO_KEYBOARD_STATE last_state;
    internal readOnly ALLEGRO_KEYBOARD_STATE now_state;
} InputService;
constructor function InputService* service_create_input_service(void);

instances.h的片段

#define Extends_Instance char             *name;                                         \
                                                char             *class_name;                                   \
                                                size_t            id;                                           \
                                                struct Instance  *parent;                                       \
                                                struct Instance  *children[MAX_CHILDREN];                       \
                                                uint32_t          children_count;                               \
                                                method           (m_draw, void)(struct Instance *self);         \
                                                method           (m_debugDraw, void)(struct Instance *self);    \
                                                hashtable_t       children_fi;                                                      \
                                                bool              enable_debugging

// & (? `@class Instance`) !
typedef struct Instance { Extends_Instance; } Instance;  !!!!!! NO ERROR HERE?? !!!!!!

编译器错误：

../placeholder/instances/services/input_service.h:16:9: error: expected specifier-qualifier-list before ‘Extends_Instance’
   16 |         Extends_Instance;
      |         ^~~~~~~~~~~~~~~~