recover_doesnt_work.go

func main() {
	defer func() {
		if r := recover(); r != nil {
			panic("never called")
		}
	}()

	// fatal error: concurrent map writes
	m := make(map[int]int)
	for i := 0; i < 100; i++ {
		go func(i int) {
			m[i] = i
		}(i)
	}
}