gistfile1.scala

  val selectedBonusIdValidator = (form: Form[BonusForm]) =>
    (for {
      value <- form.value
      bonusId <- value.selectedBonusId
    } yield form
      ) getOrElse form.withError("selectedBonusId", "You should select an item!")

  val selectedBonusValueValidator = (form: Form[BonusForm]) =>
    (for {
      value <- form.value
      bonusId <- value.selectedBonusValue
    } yield form
      ) getOrElse form.withError("selectedBonusValue", "You should provide the value!")


   val form = (bonusForm.fill(formEntity) /:
      List(selectedBonusIdValidator, selectedBonusValueValidator))((f, v) => v(f))
   if (form.hasErrors) ... else ...