test.go

package main

import (
	"fmt"
)

type DoInter interface {
	Do()
	Get() DoInter
	Set()
}

/////////////////////////////
type A struct {
	i DoInter
}

func (b *A) Do() {
	fmt.Println("aaa")
}

func (b *A) Get() DoInter {
	return b.i
}

func (b *A) run() {
	for i := 0; i < 10; i++ {
		b.Get().Do()
	}
}

//////////////////////////////////
type B struct {
	A
}

func (b *B) Do() {
	fmt.Println("bbbbb")
}
func (b *B) Set() { b.i = b }

func main() {
	b := B{}
	b.Set()
	b.run()
}