4
隐类
我尝试在重载对象的方法世界使用隐 类世界为什么不能重载无参数方法,为
class World {
}
object World {
implicit class WithWorld(_world: World) {
def world(): Unit = println("world")
}
implicit class WithWorld2(_world: World) {
def world(i: List[Int]): Unit = println("list Int")
}
implicit class WithWorld3(_world: World) {
def world(i: List[String]): Unit = println("list String")
}
}
//测试
val world = new World()
//这是正确的
world.world(List(1))
world.world(List("string"))
//但是这个world.world()
,我得到一个编译错误
Error:(36, 5) type mismatch;
found : world.type (with underlying type World)
required: ?{def world: ?}
Note that implicit conversions are not applicable because they are ambiguous:
both method WithWorld in object World of type (_world: World)World.WithWorld
and method WithWorld2 in object World of type (_world: World)World.WithWorld2
are possible conversion functions from world.type to ?{def world: ?}
world.world()
^
不要使用重载...通常这不是一个好主意。你想通过超载来实现什么? –
我只想尝试隐式类的功能 –