C/C++ offsetof直接调用结构体问题

因为gcc升级，之前的项目编译出错了，请问是什么原因？
std:size_t f_msg(){
struct t_str{
uint8_t di_n;
T di_target;
};
return offsetof(t_str, di_target);
}
error: expected primary-expression before ',' token renturn offsetof(t_str, di_target);
error: 'di_target' was not declared in this scope
renturn offsetof(t_str, di_target);