Ignore private/sealed abstract class/traits

[dwijnand]

Fixes #14579

[dwijnand]

lol

def map[F[_]](self: Tuple, f: [t] => t => F[t]): Tuple = self match {
  case EmptyTuple => self
  case _ => fromIArray(self.productIterator.map(f(_).asInstanceOf[Object]).toArray.asInstanceOf[IArray[Object]]) // TODO use toIArray
}

Error:  -- [E030] Match case Unreachable Error: /__w/dotty/dotty/library/src/scala/runtime/Tuples.scala:544:9 
Error:  544 |    case _ => fromIArray(self.productIterator.map(f(_).asInstanceOf[Object]).toArray.asInstanceOf[IArray[Object]]) // TODO use toIArray
Error:      |         ^
Error:      |         Unreachable case
Error:  one error found

Well the logic is right... outside of EmptyTuple, the Tuple class has no subclasses... 🙄 Do I special case tuple-vs-generic-tuple in SpaceEngine too??

[bishabosha]

Suggested change

	else if tp.classSymbol == defn.TupleClass || tp.classSymbol == defn.NonEmptyTupleClass then List(child) // Tuple is weird/different...
	else if tp.classSymbol == defn.TupleClass || tp.classSymbol == defn.NonEmptyTupleClass then List(child) // Tuple types are substituted for different classes at runtime

[dwijnand]

Actually, it makes me think: is there a reason TupleXXL doesn't extend Tuple and the TupleN classes made synthetically to extend Tuple? Then we wouldn't need this.