1
我有一个和特质,看起来像如下:泛型类型和类型不匹配
sealed trait Sum[+A, +B]
final case class Failure[A](value: A) extends Sum[A, Nothing]
final case class Success[B](value: B) extends Sum[Nothing, B]
当我尝试创建一个新的变量为:
val s1: Sum[Int, Nothing] = Success(4)
我有以下错误:
Error:(5, 41) type mismatch;
found : Int(4)
required: Nothing
val s1: Sum[Int, Nothing] = Success(4)
为什么?
为什么这是工作:
val s1: Sum[Int, Int] = Success(4)