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object Test{
abstract class Number
case class Int(n: int) extends Number
case class Double(d: double) extends Number
trait Term[+a]
case class Cell[a](var x: a) extends Term[a]
case class NumTerm(val n: Number) extends Term[Number]
class IntTerm(n: Int) extends NumTerm(n) with Term[Int]
def f[a](t:Term[a], c:Cell[a]): unit =
t match {
case NumTerm(n) => c.x = Double(1.0)
}
val x:Term[Number] = NumTerm(Int(5))
def main(args: Array[String]): unit = {
val cell = Cell[Int](Int(6))
Console.println(cell)
f[Int](new IntTerm(Int(5)), cell)
Console.println(cell)
}
}
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