bug: fail to copy field named with struct

[morya]

go-model won't copy filed with the same type name,

following are the reproduce code.

package main

import (
	"encoding/json"
	"log"

	"golang.org/x/oauth2"
	go_model "gopkg.in/jeevatkm/go-model.v1"
)

type Endpoint struct {
	AuthURL  string `yaml:"auth_url" validate:"required,min=1"`
	TokenURL string `yaml:"token_url" validate:"required,min=1"`

	AuthStyle oauth2.AuthStyle `yaml:"auth_style" validate:"required,oneof=0 1 2"`
}

type OauthConfig struct {
	ClientID     string `yaml:"client_id" validate:"required,min=1"`
	ClientSecret string `yaml:"client_secret" validate:"required,min=1"`
	Endpoint     Endpoint
	RedirectURL  string   `yaml:"redirect_url"  validate:"required,min=1"`
	Scopes       []string `yaml:"scopes" example:"state"`
}

func DumpJson(obj interface{}) string {
	data, _ := json.Marshal(obj)
	return string(data)
}

func main() {
	var sample = OauthConfig{
		ClientID:     "aa",
		ClientSecret: "bb",
		Endpoint: Endpoint{
			AuthURL:   "https://sample.com",
			TokenURL:  "https://sample.com",
			AuthStyle: 1,
		},
		RedirectURL: "https://sample.com",
		Scopes:      []string{"state"},
	}
	var d = oauth2.Config{}
	go_model.Copy(&d, sample)

	log.Println(DumpJson(d))
}

---

sample code output:

2022/03/24 11:16:32 {"ClientID":"aa","ClientSecret":"bb","Endpoint":{"AuthURL":"","TokenURL":"","AuthStyle":0},"RedirectURL":"https://sample.com","Scopes":["state"]}

Endpoint fields are empty.