In Scala 3 I can specify a main method which gets one parameter like this:

@main
def main(mode: String): Unit = ???

If I run it without specifying the argument, I would get “Illegal command line: more arguments expected”. Fine.

Now if I specify a default value like this

@main
def main(mode: String = "all"): Unit = ???

then I still get that same error.

1. Why is that?
2. And why doesn’t the compiler complain if default
   values are not possible in main method arguments? To just ignore them doesn’t seem useful to me.

Tried with Scala 3.4.2.