Having an embeded struct with custom marshalJSON function, make the json.Marshal to use that marshal function in the base structure.

package main

import (
    "encoding/json"
    "fmt"
)


type h0 struct {
    M []string
}

func (a h0) MarshalJSON() ([]byte, error) {
    return json.Marshal(a.M)
}

type h1 struct {
    h0 `json:"hedaer"`
    A string
    B string
}

func main() {

    v := h1{}
    v.A = "A" 
    v.B = "B"
    v.M = append(v.M, "1", "2", "3")


    a, err := json.Marshal(v)
    if err != nil {
        panic(err)
    }

    fmt.Println(string(a))
}

Output must be :

{"hedaer":["1","2","3"],"A":"A","B":"B"}

But is :

["1","2","3"]

in playground : https://play.golang.org/p/619v_hL5hh

the reason is obvious, since the function invoked on the outer structure, but I think json library must ignore this kind of marshaller functions.
I test this against the latest version of go (1.4.2) in linux, and also the git version of go .
Any other information is required?