test.go

package main

type Foo interface {
	methodA() string
}

type Bar struct {
	Foo
}

func (bar *Bar) methodA() string {
	return "foo bar"
}

func (bar *Bar) New() *Bar {
	return &Bar{}
}

type Baz struct {
	Foo *Foo
}

func main() {
	baz := Baz{Bar.New()}
}