1  struct X {
       2    int b;
       3  };
       4  
       5  typedef struct list_node *list;
       6  
       7  struct list_node {
       8    list next;
       9    list *ptr;
      10    struct X *value;
      11  };
      12  
      13  list *g(list *ptr)
      14  {
      15    return ptr;
      16  }