map[int]int failed to parse

[fananchong]

My code is :

package main

const Eight = 8

type MyInt int
type Data []byte
type Test1 map[string]int
type Test2 map[int]int

type Struct struct {
	Which  map[int]*MyInt
	Which1 Test1
	Which2 Test2
	Other  Data
	Nums   [Eight]float64
}

func main() {

}

and, shell cmd like this:

fananchong@ubuntu-vm:~/msgp_test$ msgp -file=main.go -o=main_msgp.go -v
Input: "main.go"
warn: main.go: Struct: Which: ignored
warn: main.go: Test2: failed to parse
info: main.go: Struct: inlining Test1
warn: main.go: Struct: unresolved identifier: Test2
info: main.go: Struct: inlining Data
Wrote and formatted "main_msgp.go"
Wrote and formatted "main_msgp_test.go"
fananchong@ubuntu-vm:~/msgp_test$ go build
# msgp_test
./main_msgp.go:162:18: z.Which2.DecodeMsg undefined (type Test2 has no field or method DecodeMsg)
./main_msgp.go:236:16: z.Which2.EncodeMsg undefined (type Test2 has no field or method EncodeMsg)
./main_msgp.go:284:19: z.Which2.MarshalMsg undefined (type Test2 has no field or method MarshalMsg)
./main_msgp.go:350:23: z.Which2.UnmarshalMsg undefined (type Test2 has no field or method UnmarshalMsg)
./main_msgp.go:404:19: z.Which2.Msgsize undefined (type Test2 has no field or method Msgsize)