composition.go

package main

import (
	"fmt"
)

type Foo struct {
}

func (f Foo) foo() {
	fmt.Println("foo")
}

type Bar struct {
}

func (b Bar) bar() {
	fmt.Println("bar")
}

type A struct {
	Foo
}

type B struct {
	Foo
	Bar
}

type AB struct {
	A
	B
}

func main() {
	a := A{}
	a.foo()
	a.Foo.foo()

	b := B{}
	b.foo()
	b.bar()

	ab := AB{}
	ab.B.foo()
	ab.bar()
}