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目前我正在尝试使用猫ValidatedMonad 实现自定义模型/单参数验证.但是,从1.0开始删除笛卡尔积之后,我无法使用(v1 | @ | v2)map(f)并且无法编译我的代码:

import cats.Semigroupal
import cats.data.Validated.{Invalid, Valid}
import cats.data.{ValidatedNel, _}
import cats.implicits._
import cats.instances.all._

case class FieldErrorInfo(name: String, error: String)

type FieldName = String

type ValidationResult[A] = ValidatedNel[FieldErrorInfo, A]

trait SingleFieldValidationRule[U] extends ((U, FieldName) => ValidationResult[U])

trait ModelValidationRule[M] extends (M => ValidationResult[M])

object ValidateNameRule extends SingleFieldValidationRule[String] {
  override def apply(v1: String, name: String): ValidationResult[String]  = {
    if (v1.contains("cats"))
      v1.validNel
    else
      FieldErrorInfo(name, "Some Error").invalidNel
  }
}

object ValidateQuantityRule extends SingleFieldValidationRule[Int] {
  override def apply(v1: …