Unexported copy of struct is failing

[mahadeva1989]

I have a situation where I'm not able to copy unexported struct type values to the exported base fields.

package main

import (
"fmt"

"github.com/jinzhu/copier"

)

func main() {
type common struct {
Common1 int json:"Common1"
Common2 string json:"Common2"
}

type source struct {
	Name        string `json:"Name"`
	Description string `json:"Description"`
	common
}

type destination struct {
	Name        string `json:"Name"`
	Description string `json:"Description"`
	Common1     int    `json:"Common1"`
	Common2     string `json:"Common2"`
}

src := source{Name: "name", Description: "description", common: common{Common1: 2, Common2: "common2"}}
dest := destination{}
copier.Copy(&dest, src)
fmt.Printf("values %v", dest)

}

Actual : values {name description 0 }

Expected
Please advise me on how to get the output as values {name description 2 common2}