can't work with interface var

[nowind]

code as following failed:
var m interface{}=[]int{1,2}
slType:=reflect2.TypeOf(m).(reflect2.SliceType)
slType.LengthOf(m) //<--here i can't use &m

[whisper-bye]

+1

type message struct {
        crc uint16
}

msg := &message{}
unpack(b, msg)

func unpack(b []byte, msg interface{}) error {
	buf := bytes.NewBuffer(b)
	typ := reflect2.TypeOf(msg)
	structType := typ.(*reflect2.UnsafeStructType) // panic
...

[whisper-bye]

I fingure it out, it should be reflect2.TypeOfPtr(msg).Elem()