Go语言JSON解析：自定义UnmarshalJSON后字段丢失，如何解决？

package main

import (
    "encoding/json"
    "fmt"
    "strconv"
)

type idarr struct {
    ids []uint64 `json:"ids"`
}

type a struct {
    idarr
    more string `json:"more"`
}

func (s *idarr) unmarshaljson(data []byte) error {
    type temp idarr
    t := struct {
        ids []string `json:"ids"`
        *temp
    }{
        temp: (*temp)(s),
    }
    if err := json.unmarshal(data, &t); err != nil {
        return err
    }
    for _, id := range t.ids {
        uid, err := strconv.parseint(id, 10, 64)
        if err != nil {
            return err
        }
        s.ids = append(s.ids, uint64(uid))
    }
    return nil
}

func main() {

    d := `
        {"ids":["1213334"], "more": "text"}
                        `
    a := &a{}
    json.unmarshal([]byte(d), &a)

    fmt.printf("%+v", a)
}

func (s *a) unmarshaljson(data []byte) error {
    t := struct {
        ids []string `json:"ids"`
        more string `json:"more"`
    }{}

    if err := json.unmarshal(data, &t); err != nil {
        return err
    }
    for _, id := range t.ids {
        uid, err := strconv.parseint(id, 10, 64)
        if err != nil {
            return err
        }
        s.ids = append(s.ids, uint64(uid))
    }
    s.more = t.more
    return nil
}

type A struct {
    IdArr IdArr
    More string `json:"more"`
}