Scala case类和伴生对象不能覆盖apply with diff签名

Question

我有以下代码：

case class Foo(x:Int) {
  def this(x: Int, y: Int) = this(x + y)
}

object Foo {
  def apply(x: Int, y: Int) = new Foo(x, y)
}

我收到编译错误：Error:Person is already defined as (compiler-generated) case class companion object Person这段代码必须工作，因为apply有另一个签名。可能是scala中的错误，我的scala版本是2.11.8