<stuff> is not case class or a sealed trait

[enlait]

Tethys does not derive writer for a sealed hierarchy even when writers for subtypes are explicitly defined

  import tethys._
  import tethys.jackson._
  import tethys.derivation.semiauto._


  sealed trait Foo

  object Foo {
    object Bar extends Foo
    class Baz extends Foo
  }

  implicit val BarWriter: JsonObjectWriter[Foo.Bar.type] =
    JsonWriter.obj[Foo.Bar.type]

  implicit val BazWriter: JsonObjectWriter[Foo.Baz] =
    JsonWriter.obj[Foo.Baz]

  implicit val FooWriter: JsonWriter[Foo] = jsonWriter