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case class Cell[A](var x: A)
object Test {
def f1(x: Any) = x match { case y @ Cell(_) => y } // Inferred type is Cell[Any]
def f2(x: Cell[_]) = x match { case y @ Cell(_) => y } // Inferred type is Cell[_]
def f3[A](x: Cell[A]) = x match { case y @ Cell(_) => y } // Inferred type is Cell[A]
def main(args: Array[String]): Unit = {
val x = new Cell(1)
val y = f1(x)
y.x = "abc"
println(x.x + 1)
}
}
// The tweetable variation
object Tweet {
case class C[A](f:A=>A);def f(x:Any)=x match { case C(f)=>f("") };f(C[Int](x=>x))
}
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