Modifying struct value using reflection and loop

I wanted to loop through a struct and modify fields value using reflection. How can I Set it?

func main() {
    x := struct {
        Foo string
        Bar int
    }{"foo", 2}
    StructCheck(Checker, x)
}

func Checker(s interface{}) interface{} {
    log.Println(s)
    return s
}

func StructCheck(check func(interface{}) interface{}, x interface{}) interface{} {
    v := reflect.ValueOf(x)
    for i := 0; i < v.NumField(); i++ {
        r := check(v.Field(i))
        w := reflect.ValueOf(&r).Elem()

        log.Println(w.Type(), w.CanSet())

        // v.Field(i).Set(reflect.ValueOf(w))

    }
    return v
}

Running Set() causes panic and shows :reflect.Value.Set using unaddressable value