Unable to mock method with optional default arguments

[ewerkema]

We are not able to mock methods that use optional default arguments. This problem occurs on Java 21 and using mockito-scala 1.17.37:

test("bla") {
  trait Mockable {
    def doTheThing(a: Option[Int] = None): UIO[Int]
  }

  val mockable = mock[Mockable]
  when(mockable.doTheThing()).thenReturn(ZIO.succeed(43))

  for {
    _ <- mockable.doTheThing()
  } yield assertCompletes
}

The error it produces is the following:

  - TestFacility - bla
    Exception in thread "zio-fiber-252" org.mockito.exceptions.verification.SmartNullPointerException: 
    You have a NullPointerException here:
    -> at org.scalactic.DefaultPrettifier.prettifyCollection(Prettifier.scala:188)
    because this method call was *not* stubbed correctly:
    -> at scala.Option.orElse(Option.scala:477)
    mockable$1.doTheThing$default$1();
    
    	at org.scalactic.DefaultPrettifier.prettifyCollection(Prettifier.scala:188)
    	at org.scalactic.DefaultPrettifier.prettify(Prettifier.scala:218)
    	at org.scalactic.DefaultPrettifier.apply(Prettifier.scala:223)
    	at TestFacilitySpec$.$anonfun$spec$37(TestFacilitySpec.scala:125)
    	at TestFacilitySpec.spec(TestFacilitySpec.scala:116)

It does seem to work when updating mockito-core to 5.14.2