scala> sealed abstract class Box[+A]; case class BoxF[A](f: A => A) extends Box[A]
defined class Box
defined class BoxF

scala> def blah = ((BoxF((_:Int)+1):Box[AnyVal]) match {case BoxF(f) => f; case _ => ???})
blah: A => A

scala> def blah2 = (blah, blah)
blah2: (A => A, A => A)

scala> blah2 : ((A => A, A => A) forSome {type A})
res0: (A => A, A => A) forSome { type A } = (<function1>,<function1>)

scala> def blah3 = blah : ((A => A) forSome {type A})
blah3: A => A forSome { type A }

scala> def blah4 = (blah3, blah3)
blah4: (A => A, A => A) forSome { type A; type A }

scala> blah4 : ((A => A, A => A) forSome {type A})
<console>:14: error: type mismatch;
 found   : (A(in value res1) => A(in value res1), (some other)A(in value res1) => (some other)A(in value res1)) where type (some other)A(in value res1), type A(in value res1)
 required: (A => A, A => A) forSome { type A }

              blah4 : ((A => A, A => A) forSome {type A})
              ^