var x int
	_ = x
	var wg sync.WaitGroup
	n := 1
	for i := 0; i < n; i++ {
		wg.Add(1)
		j := i
		go func() {
			x = j
			wg.Done()
		}()
	}
	wg.Wait()
}

func TestRaceWaitGroup(t *testing.T) {
	var x int
	_ = x
	var wg sync.WaitGroup
	n := 2
	for i := 0; i < n; i++ {
		wg.Add(1)
		j := i
		go func() {
			x = j
			wg.Done()
		}()
	}
	wg.Wait()
}