jsonのfieldが23個以上どうするんだ？エラーは１つではなく複数返したい。

sample.scala

import cats.data.Validated.{Invalid, Valid}
import cats.syntax.apply._
import io.circe.generic.semiauto.deriveEncoder
import io.circe.parser.decodeAccumulating
import io.circe.{Encoder, _}
import io.tabmo.circe.extra.rules.IntRules
import io.tabmo.json.rules._

/**
 * 下記の方法はfield 22個まででの対応方法がわかんない。複数のErrorが帰る
 * forで書き換えるとfail-fastで１つのエラーが発見されると終了になってしまう。
 */
object Test {

  case class Large(
                    a: Int,
                    b: Int,
                    c: Int,
                    d: Int,
                    e: Int,
                    f: Int,
                    g: Int,
                    h: Int,
                    i: Int,
                    j: Int,
                    k: Int,
                    l: Int,
                    m: Int,
                    n: Int,
                    o: Int,
                    p: Int,
                    q: Int,
                    r: Int,
                    s: Int,
                    t: Int,
                    u: Int,
                    v: Int,
                    //                  w: Int,
                    //                  x: Int,
                    //                  y: Int,
                    //                  z: Int
                  )


  implicit val encoder: Encoder[Large] = deriveEncoder[Large]
  implicit val decoder: Decoder[Large] = (
    Decoder.instance(_.downField("a").read(IntRules.positive())),
    Decoder.instance(_.downField("b").read(IntRules.positive())),
    Decoder.instance(_.downField("c").read(IntRules.positive())),
    Decoder.instance(_.downField("d").read(IntRules.positive())),
    Decoder.instance(_.downField("e").read(IntRules.positive())),
    Decoder.instance(_.downField("f").read(IntRules.positive())),
    Decoder.instance(_.downField("g").read(IntRules.positive())),
    Decoder.instance(_.downField("h").read(IntRules.positive())),
    Decoder.instance(_.downField("i").read(IntRules.positive())),
    Decoder.instance(_.downField("j").read(IntRules.positive())),
    Decoder.instance(_.downField("k").read(IntRules.positive())),
    Decoder.instance(_.downField("l").read(IntRules.positive())),
    Decoder.instance(_.downField("m").read(IntRules.positive())),
    Decoder.instance(_.downField("n").read(IntRules.positive())),
    Decoder.instance(_.downField("o").read(IntRules.positive())),
    Decoder.instance(_.downField("p").read(IntRules.positive())),
    Decoder.instance(_.downField("q").read(IntRules.positive())),
    Decoder.instance(_.downField("r").read(IntRules.positive())),
    Decoder.instance(_.downField("s").read(IntRules.positive())),
    Decoder.instance(_.downField("t").read(IntRules.positive())),
    Decoder.instance(_.downField("u").read(IntRules.positive())),
    Decoder.instance(_.downField("v").read(IntRules.positive()))
    ).mapN(Large.apply)


  def main(args: Array[String]): Unit = {
    val text = """{"a":"a", "b":"b", "c":3, "d":4, "e":5, "f":6, "g":7, "h":8, "i":9, "j":10, "k":11, "l":12, "m":13, "n":14, "o":15, "p":16, "q":17, "r":18, "s":19, "t":20, "u":21, "v":22}"""

    val result = decodeAccumulating(text)(decoder) match {
      case Valid(value) => Right(value)
      case Invalid(errors) =>
        Left(errors)

    }
    // "a":"a", "b":"b"で文字2つのエラー
    println(result.left.get.size == 2)
    println(result)
  }
}