Golang 空指针异常踩坑

package main

import "fmt"

type Response struct {
    Code    int
    Message string
}

func main() {
    r, err := Do()
    if err != nil {
        return
    }
    fmt.Println(r)
}

func Do() (res *Response, err error) {
    // res = &Response{}
    res.Code = 200
    res.Message = "ok"
    return
}

没加 res = &Response{} 会空指针异常