package main

type fooInterface interface {
    foo()
}

type barInterface interface {
    bar(foo fooInterface)
}

type a struct {
}

func (a a) foo() {
    println("a.foo")
}

func (a a) bar(foo fooInterface) {
    foo.foo()
    println("a.bar")
}

type b struct {
    a
}

func (b b) foo() {
    println("b.foo")
}

func main() {
    var a = a{}
    a.bar(a)

    var b = b{}
    b.bar(b)
}