package test

trait Vector[+A] {
  def append(x: Vector[A]): Vector[A]
  private[this] def append3(x: Vector[A]): Vector[A] = append(x)
}

class C[T]

object Covariant {
  class Foo[+A] {
    private[this] var a : A = _
    def getA : A = a
    // allowed
    private[this] def setA1(a : A) = this.a = a
    protected[this] def setA2(a : A) = this.a = a
    // forbidden
    private def setA3(a : A) = this.a = a
    protected def setA4(a : A) = this.a = a

    object Baz extends C[A]
    trait Convert[B] {
      def b2a(b : B) : A
      def doit1(b : B) = setA1(b2a(b))
      def doit2(b : B) = setA2(b2a(b))
      def doit3(b : B) = setA3(b2a(b))
      def doit4(b : B) = setA4(b2a(b))
    }
  }
  class Foo2[+A] {
    private[this] var a : A = _
    def getA : A = a
    private[this] def setA(a : A) = this.a = a

    {
      trait Convert[B] {
        def b2a(b : B) : A
        def doit(b : B) = setA(b2a(b))
      }
      println("")
    }
  }
  class Foo3[+A] {
    private[this] var a : A = _
    def getA : A = a
    private[this] def setA(a : A) = this.a = a

    private[this] trait Convert[B] {
      def b2a(b : B) : A
      def doit(b : B) = setA(b2a(b))
    }
  }
  abstract class AbstractTest {
    val a : Foo[AnyRef]
    val c = new a.Convert[Int] {
      def b2a(b : Int) : AnyRef = "hello"
    }
    val b : Int = 42
  }
  class Test extends AbstractTest {
    val a : Foo[java.lang.Character] = new Foo[java.lang.Character]
  }
  def main(args : Array[String]): Unit = {
    val test = new Test
    test.c.doit1(test.b)
    test.c.doit2(test.b)
    test.c.doit3(test.b)
    test.c.doit4(test.b)
    val x : java.lang.Character = test.a.getA
    Console.println("XXX " + x)
  }

  abstract class T[+A] {
    val x: T[A] {
      val m: A => A
    }
  }
  object ST extends T[String] {
    val x: T[String] { val m: String => String } = ST
    val m: String => String = (_.substring(1))
  }
  val t: T[Any] = ST
  t.x.m(new Object)
}

object TestAlias {
  class B[-T]
  trait C[+T] {
    type A = T
    def foo: B[A]
  }
}