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