3 files changed, 15 insertions, 1 deletions
diff --git a/src/library/scala/collection/BufferedIterator.scala b/src/library/scala/collection/BufferedIterator.scala
index e6e97d584c..1424ef2fd0 100644
--- a/src/library/scala/collection/BufferedIterator.scala
+++ b/src/library/scala/collection/BufferedIterator.scala
@@ -24,5 +24,11 @@ trait BufferedIterator[+A] extends Iterator[A] {
    */
   def head: A
 
+  /** Returns an option of the next element of an iterator without advancing beyond it.
+    * @return  the next element of this iterator if it has a next element
+    *           `None` if it does not
+    */
+  def headOption : Option[A] = if (hasNext) Some(head) else None
+
   override def buffered: this.type = this
 }
diff --git a/src/library/scala/collection/immutable/Queue.scala b/src/library/scala/collection/immutable/Queue.scala
index 3ad6656636..1dd0d7683a 100644
--- a/src/library/scala/collection/immutable/Queue.scala
+++ b/src/library/scala/collection/immutable/Queue.scala
@@ -84,6 +84,14 @@ sealed class Queue[+A] protected(protected val in: List[A], protected val out: L
     else if (in.nonEmpty) new Queue(Nil, in.reverse.tail)
     else throw new NoSuchElementException("tail on empty queue")
 
+  /* This is made to avoid inefficient implementation of iterator. */
+  override def forall(p: A => Boolean): Boolean =
+    in.forall(p) && out.forall(p)
+
+  /* This is made to avoid inefficient implementation of iterator. */
+  override def exists(p: A => Boolean): Boolean =
+    in.exists(p) || out.exists(p)
+
   /** Returns the length of the queue.
    */
   override def length = in.length + out.length
diff --git a/src/library/scala/collection/immutable/Range.scala b/src/library/scala/collection/immutable/Range.scala
index 2e56750115..82203b3d1a 100644
--- a/src/library/scala/collection/immutable/Range.scala
+++ b/src/library/scala/collection/immutable/Range.scala
@@ -437,7 +437,7 @@ object Range {
   def count(start: Int, end: Int, step: Int): Int =
     count(start, end, step, isInclusive = false)
 
-  class Inclusive(start: Int, end: Int, step: Int) extends Range(start, end, step) {
+  final class Inclusive(start: Int, end: Int, step: Int) extends Range(start, end, step) {
 //    override def par = new ParRange(this)
     override def isInclusive = true
     override protected def copy(start: Int, end: Int, step: Int): Range = new Inclusive(start, end, step)