Ad-hoc polymorphism for reflection created case classes Scala

Question

I need to implement Ad-hoc polymorphism, consider this code:

  trait BlockInputRequest

  case class StaticBlockInput(
    content: String
  ) extends BlockInputRequest

  case class StaticBlockOutput(
    content: String = ""
  )

  trait BlockProcessor[T] {
    def processBlock(request: T, project: String, userEmail: String, empty: Boolean = false)(implicit ec: ExecutionContext): Future[Any]
  }

  implicit val StaticBlockInputProcessor: BlockProcessor[StaticBlockInput] = new BlockProcessor[StaticBlockInput] {
    override def processBlock(request: StaticBlockInput, project: String, userEmail: String, empty: Boolean)(implicit ec: ExecutionContext): Future[Any] = {
      Future.successful(
        if (empty)
          StaticBlockOutput()
        else
          StaticBlockOutput(request.content)
      )
    }
  }

  implicit class BlockProcessorOps[T](request: T)(implicit ev: BlockProcessor[T]) {
    def processBlock(project: String, userEmail: String, empty: Boolean): Future[Any] = ev.processBlock(request, project, userEmail, empty)
  }

Then I have no problems to run something like:

StaticBlockInput("test string").processBlock("myProject","[email protected]",false)

But what if my input was created by reflection from some other part of code and actual class type is erased and all I have is an instance of generic type and manifest:

val manifest: Manifest[I <: BlockInputRequest] = ... // type is saved
val block: BlockInputRequest = ... // created using reflection
block.processBlock("myProject","[email protected]",false)

Is there a way I can resolve BlockProcessor? Or maybe I can use reflection again in some way?