Scala: "Parameter type in structural refinement may not refer to an abstract type defined outside th
- by raichoo
Hi, I'm having a problem with scala generics. While the first function I defined here seems to be perfectly ok, the compiler complains about the second definition with:
error: Parameter type in structural refinement may not refer to an abstract type defined outside that refinement
def >>[B](a: C[B])(implicit m: Monad[C]): C[B] = {
^
What am I doing wrong here?
trait Lifter[C[_]] {
implicit def liftToMonad[A](c: C[A]) = new {
def >>=[B](f: A => C[B])(implicit m: Monad[C]): C[B] = {
m >>= (c, f)
}
def >>[B](a: C[B])(implicit m: Monad[C]): C[B] = {
m >> a
}
}
}
IMPORTANT: This is NOT a question about Monads, it's a question about scala polymorphism in general.
Regards,
raichoo
