Can't derive a type that involves a hierarchy of traits + scalajs

Input

class Field {}

class Abc {
  def p: (Field, Map[String, String]) = (null, null)
}

Output

[error] Couldn't derive type uni.Abc
[error]       read[uni.Abc]("")

[DavidPerezIngeniero]

This runs ok from the REPL in Ammonite:

import upickle.default._

case class Datos(@key("Bytes enviados/min") enviados: Int,
                 Conectados: Int,
                 @key("Bytes recibidos/min") recibidos: Int,
                 @key("Tramas/min") tramas: Int,
                 @key("ErroresPost/min") errores: Int,
                 @key("Post/min") post: Int)
val d = read[Datos](".....")

but fails to compile when used inside an Ammonite script:

Couldn't derive type Datos
                val d = read[Datos]("......")

Should I open another bug issue?

[DavidPerezIngeniero]

Solved by making Datos a top level class, instead of nested inside a function.