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import scala.language.implicitConversions
// the classes involved
case class Z[U](a: U)
case class Intermediate[T, U](t: T, u: U)
class Implicit1[T](b: Implicit2[T])
class Implicit2[T](c: Implicit3[T])
class Implicit3[T](/* and so on */)
object Test extends App {
// the base conversion
implicit def convertToZ[T](a: A[T])(implicit b: Implicit1[T]): Z[A[T]] = Z(a)
// and the implicit chaining, don't you just love it? :D
// implicit1, with one alternative
implicit def implicit1[T <: Intermediate[_, _]](implicit b: Implicit2[T]) = new Implicit1[T](b)
// implicit2, with two alternatives
implicit def implicit2alt1[T <: Intermediate[_ <: String, _]](implicit c: Implicit3[T]) = new Implicit2[T](c)
implicit def implicit2alt2[T <: Intermediate[_ <: Double, _]](implicit c: Implicit3[T]) = new Implicit2[T](c)
// implicit3, with two alternatives
implicit def implicit3alt1[T <: Intermediate[_, _ <: Int]] = new Implicit3[T]()
implicit def implicit3alt2[T <: Intermediate[_ <: Double, _ <: AnyRef],X] = new Implicit3[T]()
// and our targets
/** conversion here, with constraints */
class A[T]()
(new A).a
(new A[Nothing]).a
}
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