Try to bypass separation check in case body

Author: noti0na1

scala2-library-cc/src/scala/collection/View.scala

@@ -152,8 +152,9 @@ object View extends IterableFactory[View] {
     def apply[A](underlying: Iterable[A]^, p: A => Boolean, isFlipped: Boolean): Filter[A]^{underlying, p} =
       underlying match {
         case filter: Filter[A] if filter.isFlipped == isFlipped =>
-          new Filter(filter.underlying, a => filter.p(a) && p(a), isFlipped)
-            .asInstanceOf[Filter[A]^{underlying, p}]
+          unsafeAssumeSeparate:
+            new Filter(filter.underlying, a => filter.p(a) && p(a), isFlipped)
+              .asInstanceOf[Filter[A]^{underlying, p}]
               // !!! asInstanceOf needed once paths were added, see path-patmat-should-be-pos.scala for minimization
         //case filter: Filter[A]^{underlying} if filter.isFlipped == isFlipped =>
         //  unsafeAssumeSeparate: