switch case fallthrough-like recursive flow

FallthroughRecursiveWhen.kt

fun verify(driver: TestDriver) {
  // a switch case fallthrough-like recursive flow
  tailrec fun verify(verification: Verification) {
    when (verification) {
      NO_VERIFICATION -> return // THE END
      VERIFY_PHASE_1 -> verifyPhase1(driver)
      VERIFY_PHASE_2 -> verifyPhase2(driver)
      VERIFY_PHASE_3 -> verifyPhase3(driver)
      VERIFY_PHASE_4 -> verifyPhase4(driver)
    }
    verify(verification.prev()) // fall-through!
  }
  verify(verification)
}

enum class Verification { NO_VERIFICATION, VERIFY_PHASE_1, VERIFY_PHASE_2, VERIFY_PHASE_3, VERIFY_PHASE_4 }

inline fun <reified T : Enum<T>> T.prev(): T {
  val values = enumValues<T>()
  val prevOrdinal = (ordinal - 1) % values.size
  return values[prevOrdinal]
}

inline fun <reified T : Enum<T>> T.next(): T {
  val values = enumValues<T>()
  val nextOrdinal = (ordinal + 1) % values.size
  return values[nextOrdinal]
}

FallthroughSwitch.java

@SuppressWarnings("unused") class Verifications {

  private final Verification verification = Verification.NO_VERIFICATION;

  void verify(TestDriver driver) {
    switch (verification) {
      case VERIFY_PHASE_4:
        verifyPhase4(driver);
      case VERIFY_PHASE_3:
        verifyPhase3(driver);
      case VERIFY_PHASE_2:
        verifyPhase2(driver);
      case VERIFY_PHASE_1:
        verifyPhase1(driver);
      case NO_VERIFICATION:
    }
  }


  private void verifyPhase1(TestDriver driver) {}
  private void verifyPhase2(TestDriver driver) {}
  private void verifyPhase3(TestDriver driver) {}
  private void verifyPhase4(TestDriver driver) {}

  static class TestDriver {

  }
}

NoFallthroughWhen.kt

fun verify(driver: TestDriver) =
    when (verification) {
      NO_VERIFICATION -> Unit
      VERIFY_PHASE_1 -> verifyPhase1(driver)
      VERIFY_PHASE_2 -> {
        verifyPhase1(driver)
        verifyPhase2(driver)
      }
      VERIFY_PHASE_3 -> {
        verifyPhase1(driver)
        verifyPhase2(driver)
        verifyPhase3(driver)
      }
      VERIFY_PHASE_4 -> {
        verifyPhase1(driver)
        verifyPhase2(driver)
        verifyPhase3(driver)
        verifyPhase4(driver)
      }
    }