Method taking implicit CanBuildFrom does not work with eta-expansion?

Question

I have a following method:

def firstAndLast[CC, A, That](seq: CC)(implicit asSeq: CC => Seq[A], cbf: CanBuildFrom[CC, A, That]): That = {
  val b = cbf(se         


        

Answer 1

Not a full answer to your question, but I’ve just noticed that this works:

List("abc", "def") map firstAndLast[String, Char, String]

It then means that the type inferencer is having trouble determining the right type parameters for firstAndLast, but I wouldn’t know how to fix it…