Rewrite of ...View classes to not use existential types.

Author: odersky

src/library/scala/collection/IterableView.scala

@@ -23,7 +23,7 @@ trait IterableView[+A, +Coll] extends IterableViewLike[A, Coll, IterableView[A,
  *  `IterableView`s work. Its definitions are generally not accessed directly by clients.
  */
 object IterableView {
-  type Coll = TraversableView[_, C] forSome {type C <: Traversable[_]}
+  type Coll = TraversableView[_, _ <: Traversable[_]]
   implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, IterableView[A, Iterable[_]]] =
     new CanBuildFrom[Coll, A, IterableView[A, Iterable[_]]] {
       def apply(from: Coll) = new NoBuilder

src/library/scala/collection/SeqView.scala

@@ -23,7 +23,7 @@ trait SeqView[+A, +Coll] extends SeqViewLike[A, Coll, SeqView[A, Coll]]
  *  `SeqView`s work. Its definitions are generally not accessed directly by clients.
  */
 object SeqView {
-  type Coll = TraversableView[_, C] forSome {type C <: Traversable[_]}
+  type Coll = TraversableView[_, _ <: Traversable[_]]
   implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, SeqView[A, Seq[_]]] =
     new CanBuildFrom[Coll, A, SeqView[A, Seq[_]]] {
       def apply(from: Coll) = new NoBuilder

src/library/scala/collection/TraversableView.scala

@@ -27,7 +27,7 @@ object TraversableView {
     def result() = throw new UnsupportedOperationException("TraversableView.Builder.result")
     def clear() {}
   }
-  type Coll = TraversableView[_, C] forSome {type C <: Traversable[_]}
+  type Coll = TraversableView[_, _ <: Traversable[_]]
   implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, TraversableView[A, Traversable[_]]] =
     new CanBuildFrom[Coll, A, TraversableView[A, Traversable[_]]] {
       def apply(from: Coll) = new NoBuilder