Scala example source code file (ticket2251.scala)

This example Scala source code file (ticket2251.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

a, a, b, b, c, c, d, d, data, list

The Scala ticket2251.scala source code

// Martin: I am not sure this is a solvable problem right now. I'll leave it in pending.
// derived from pos/bug1001
class A
trait B[T <: B[T]] extends A
class C extends B[C]
class D extends B[D]

class Data {
  // force computing lub of C and D (printLubs enabled:)

/*
lub of List(D, C) at depth 2
  lub of List(D, C) at depth 1
    lub of List(D, C) at depth 0
    lub of List(D, C) is A
  lub of List(D, C) is B[_1] forSome { type _1 >: D with C <: A }
lub of List(D, C) is B[_2] forSome { type _2 >: D with C{} <: B[_1] forSome { type _1 >: D with C{} <: A } }
*/
// --> result = WRONG

  // should be: B[X] forSome {type X <: B[X]} -- can this be done automatically? for now, just detect f-bounded polymorphism and fall back to more coarse approximation

  val data: List[A] = List(new C, new D)
}