没睡的 gopher 卷王请进

func TestClose(t *testing.T) {
	rand.Seed(time.Now().UnixNano())
	wg := sync.WaitGroup{}
	wg.Add(1)
	go func() {
		defer wg.Done()
		stop := make(chan struct{})
		// goroutine 1
		go func() {
			for range stop {
				return
			}
		}()
		// goroutine 2
		go func() {
			defer close(stop)
			for {
				if rand.Intn(10) < 3 {
					return
				}
			}
		}()
		<-stop
	}()
	wg.Wait()
}

什么情况下 goroutine2 退出了但是 1 没退出