libraryDependencies += "com.github.scalaprops" %% "scalaprops-magnolia" % "0.9.0"Import the content of scalaprop.ScalapropsMagnolia close to where you want scalaprops.Gen type classes to be automatically available for case classes / sealed hierarchies,
import scalaprops.{Gen, Cogen}
import scalaprops.ScalapropsMagnoliaGen._
import scalaprops.ScalapropsMagnoliaCogen._
sealed trait X
case class Y(value: Boolean) extends X
case class Z(value: Int) extends X
Gen[X] // automatically available Gen[X] instance !
Cogen[X] // automatically available Cogen[X] instance !