Why do case classes extend only Product and not Product1, Product2, …, ProductN?

Question

after I learned that case classes extend Product, I wondered why they do not extend ProductN. E.g., given a code like:

case class Foo(a: Int)

I

Answer 1

I brought it back shortly after martin said we could do it. It doesn't work right yet, but to the extent that it does, it's behind -Xexperimental in trunk builds.

scala> case class Foo[T, U](x1: T, x2: U)
defined class Foo

scala> Foo(List("a"), "b")
res0: Foo[List[java.lang.String],java.lang.String] = Foo(List(a),b)

scala> res0.isInstanceOf[Product2[_,_]]
res1: Boolean = true