tupled.scala

case class User(name: String, email: String)
object User {} // <--- Notice this part here
// https://groups.google.com/forum/#!topic/scala-user/jyWBMz5Qslw

class Users(tag: Tag) extends Table[User](tag, "User") {
  def name = column[String]("name", O.NotNull, O.PrimaryKey)
  def email = column[String]("first", O.NotNull)
  def * = (name, email) <> (User.tupled, User.unapply)
  //             Compile complains here ---^
}