ValidationNel Error after upgrading Scalaz to 7.2

问题:

I'm running into validation issues after upgrading the Scalaz version to 7.2. The following code was working in prior Scalaz version.

 def registerOrUpdate(enc: EncAdt, dx: List[DiagnosisAdt], provs: List[Provider], plans: List[InsurancePlan]): ValidationNel[AdtError, String \/ Int] = {
        // First check that admit date is after contract start
        enc.admitDT.fold[ValidationNel[AdtError, String \/ Int]](
          MissingAdmitDate(enc).failureNel
        ) { admitTstamp =>
          val beforeContractDate = fac.dosStart.exists(_ isAfter new DateTime(admitTstamp.getTime))
          if (enc.accountNumber.trim == "") {

            MissingFin(enc).failureNel
          } else {
             ...

After upgrading Scalaz version following issue is being generated.

fold does not take type parameters

Any solution is appreciable.

回答1:

Since you again didn't provide a Minimal, Complete, and Verifiable example in your question, it is hard to help you properly. Still if I copy the first AdtValidation from my previous answer:

object AdtValidation {

  type AdtValidation[A] = ValidationNel[AdtError, A]

  implicit class AdtValidationSuccess[A](val value: A) extends AnyVal {
    def successAdt: AdtValidation[A] = Validation.success[NonEmptyList[AdtError], A](value)
  }

  implicit class AdtValidationFailure(val value: AdtError) extends AnyVal {
    def failureAdt[A]: AdtValidation[A] = Validation.failureNel[AdtError, A](value)
  }
}

then the following simplification of your code compiles for me (provided you define other classes such as EncAdt or MissingAdmitDate)

import AdtValidation._

// the original works as well but this seems better to me
def registerOrUpdate(enc: EncAdt): AdtValidation[String \/ Int] = {
//def registerOrUpdate(enc: EncAdt): ValidationNel[AdtError, String \/ Int] = {
  // First check that admit date is after contract start
  enc.admitDT.fold[ValidationNel[AdtError, String \/ Int]](
    //  MissingAdmitDate(enc).failureNel
    MissingAdmitDate(enc).failureAdt
  ) { admitTstamp =>
    //        val beforeContractDate = fac.dosStart.exists(_ isAfter new DateTime(admitTstamp.getTime))
    if (enc.accountNumber.trim == "") {

      // MissingFin(enc).failureNel
      MissingFin(enc).failureAdt
    } else {
      //...
      -\/(enc.transactionID.toString).successNel  // this works
      -\/(enc.transactionID.toString).successAdt  // this also works

    }
  }
}

Hope this helps.