参数化特征mixins

Question

是否可以参数化一个或多个混合特征？我的下面的例子没有编译，但IntelliJ的intellisense确实提出了正确的类型。

class Student
class Students[A <: Student] {

  def create = new Student with A
}

trait Major extends Student
trait Dormitory extends Student
trait Fraternity extends Student

val onCampus = new Students[Major with Dormitory]
val fratBoys = new Students[Major with Fraternity]

onCampus.create // is a: Student with Major with Dormitory
fratBoys.create // is a: Student with Major with Fraternity

Answer 1

动态混合特征是不可能的，因为Scala编译器为每个mixin生成一个新的匿名类，以在JVM上支持此功能：

scala> trait A
defined trait A

scala> trait B
defined trait B

scala> new A with B
res0: A with B = $anon$1@40f8335a

这个问题有几个类似的问题，详细解答为什么动态不可能以及如何使用宏来完成（但实际上不应该！）。

Mixing in a trait dynamically

Dynamic mixin in Scala - is it possible?

How do I create an instance of a trait in a generic method in scala?