Update whitelist with more files that compile

Thanks to the previous commit, more files now compile without deep
subtyping errors.

Author: smarter

test/dotc/scala-collections.whitelist

@@ -279,20 +279,23 @@
 ./scala-scala/src/library/scala/collection/generic/IsTraversableOnce.scala
 ./scala-scala/src/library/scala/collection/generic/IterableForwarder.scala
 
-# [error] Test dotc.tests.compileStdLib failed: java.lang.Error: deep subtype
-# fails if any of those classes are added:
-#./scala-scala/src/library/scala/collection/generic/MapFactory.scala
-#./scala-scala/src/library/scala/collection/generic/MutableMapFactory.scala
-#./scala-scala/src/library/scala/collection/generic/MutableSetFactory.scala
-#./scala-scala/src/library/scala/collection/generic/MutableSortedSetFactory.scala
+./scala-scala/src/library/scala/collection/generic/MapFactory.scala
+./scala-scala/src/library/scala/collection/generic/MutableMapFactory.scala
+./scala-scala/src/library/scala/collection/generic/MutableSetFactory.scala
+./scala-scala/src/library/scala/collection/generic/ParMapFactory.scala
+./scala-scala/src/library/scala/collection/generic/SeqFactory.scala
+./scala-scala/src/library/scala/collection/generic/SortedMapFactory.scala
+./scala-scala/src/library/scala/collection/generic/SortedSetFactory.scala
+./scala-scala/src/library/scala/collection/generic/SetFactory.scala
+
+# deep subtype
 #./scala-scala/src/library/scala/collection/generic/ParFactory.scala
-#./scala-scala/src/library/scala/collection/generic/ParMapFactory.scala
-#./scala-scala/src/library/scala/collection/generic/ParSetFactory.scala
-#./scala-scala/src/library/scala/collection/generic/SeqFactory.scala
-#./scala-scala/src/library/scala/collection/generic/SortedMapFactory.scala
-#./scala-scala/src/library/scala/collection/generic/SortedSetFactory.scala
-#./scala-scala/src/library/scala/collection/generic/SetFactory.scala
 
+# https://github.com/lampepfl/dotty/issues/974
+#./scala-scala/src/library/scala/collection/generic/MutableSortedSetFactory.scala
+
+# cyclic reference, maybe related to #974
+#./scala-scala/src/library/scala/collection/generic/ParSetFactory.scala
 
 ./scala-scala/src/library/scala/collection/generic/OrderedTraversableFactory.scala
 ./scala-scala/src/library/scala/collection/generic/SeqForwarder.scala