Add sources of synthetic classes to sources jar

[Florian3k]

Closes #20073

[sjrd]

It makes no sense for this type to be final. It definitely has subclasses, including AnyRef.

Suggested change

	final abstract class AnyKind
	abstract class AnyKind

[Florian3k]

I based it on Definitions.scala:

scala3/compiler/src/dotty/tools/dotc/core/Definitions.scala

Lines 450 to 451 in 75a15c2

	@tu lazy val AnyKindClass: ClassSymbol = {
	val cls = newCompleteClassSymbol(ScalaPackageClass, tpnme.AnyKind, AbstractFinal | Permanent, Nil, newScope(0))

When trying to extend AnyKind, the following errors are reported:

$ scala-cli repl            
Welcome to Scala 3.4.2 (11, Java OpenJDK 64-Bit Server VM).
Type in expressions for evaluation. Or try :help.
                                                                                                                                                                                                                                                   
scala> class Test extends AnyKind
-- [E093] Syntax Error: --------------------------------------------------------
1 |class Test extends AnyKind
  |      ^
  |      class Test cannot extend final class AnyKind
  |
  | longer explanation available when compiling with `-explain`
-- Error: ----------------------------------------------------------------------
1 |class Test extends AnyKind
  |                   ^^^^^^^
  |                   AnyKind does not have a constructor
2 errors found

[sjrd]

Definitions is what works for the compiler with the minimum amount of work. From a spec point of view, AnyKind is not even a class (nor a trait). It's a completely unique thing. The error message that you mention is definitely not a good message. We shouldn't tailor the doc to that poor message. We should tailor it to the real spec as much as possible instead.

(Arguably it should even be an abstract type as well, but since Nothing is presented as a class, it makes "less not" sense to also use a class here.)

[dwijnand]

The docs even say "It is declared abstract and final"

[dwijnand]

Suggested change

	/** The super-type of all types.
	/** AnyKind plays a special role in Scala's subtype system:
	* It is a supertype of all other types no matter what their kind is.

[Florian3k]

This docstring is copied from Definitions.scala:

scala3/compiler/src/dotty/tools/dotc/core/Definitions.scala

Lines 2453 to 2458 in 010ed5a

	add(AnyKindClass,
	"""/** The super-type of all types.
	| *
	| * See [[https://docs.scala-lang.org/scala3/reference/other-new-features/kind-polymorphism.html]].
	| */
	""".stripMargin)

It is also source of truth for scaladoc generation. I think those comments should be kept in sync.
Should I change it in Definitions.scala as well?

[dwijnand]

Yes please!

[dwijnand]

LGTM, but I do think the docs page description for AnyKind is better.

[dwijnand]

@WojciechMazur what about the change to the AnyKind docs in the comments?