In enum with type parameter, can't call constructor for enum case with default argument

[joan38]

Default parameters on enum cases does not seem to work properly.

Minimized code

enum Parser[+Value]:
  case Success(value: Value, issues: Seq[Failure] = Seq.empty) extends Parser[Value]
  case Failure(exception: Throwable)                           extends Parser[Nothing]

Parser.Success(1)
^
method $lessinit$greater$default$2 in object Success does not take type parameters

https://scastie.scala-lang.org/xZ81zFUkSECDcf2vpVgG1g

Workaround

enum Parser[+Value]:
  case Success[+Value](value: Value, issues: Seq[Failure] = Seq.empty) extends Parser[Value]
  case Failure(exception: Throwable)                                   extends Parser[Nothing]

Parser.Success(1)

https://scastie.scala-lang.org/avT9leMZRJmC0VMP14UeoA

[bishabosha]

wow I'm surprised no one tried this before (like me)

[joan38]

Thanks @kasiaMarek and everyone. Amazing work!

[joan38]

Sounds like this one is not completely solved in 3.6.3:

enum Parser[+Value]:
  case Success(value: Value, issues: Seq[Failure] = Seq.empty)
  case Failure(exception: Throwable) extends Parser[Nothing]

Parser.Success(1)
^
method $lessinit$greater$default$2 in object Success does not take type parameters

But the following works:

Parser.Success(1), Seq.empty)

Thanks

[joan38]

Sorry I just saw the fix will be released in 3.6.4