My swift isn't good, but since you didn't specify a type for x, I think it should compile anyway. But if things is an empty array of T, first may return nil and

My swift isn't good, but since you didn't specify a type for x, I think it should compile anyway. But if things is an empty array of T, first may return nil and x will be of type T?. If things is an array of optional, x will be of type T??