Merge pull request #348 from julienrf/indexed-seq-reverse-iterator

Pull up reverseIterator implementation from Vector to IndexedSeq

collections/src/main/scala/strawman/collection/IndexedSeq.scala

@@ -1,7 +1,7 @@
 package strawman
 package collection
 
-import scala.{Any, Int}
+import scala.{Any, Boolean, Int}
 
 /** Base trait for indexed sequences that have efficient `apply` and `length` */
 trait IndexedSeq[+A] extends Seq[A] with IndexedSeqOps[A, IndexedSeq, IndexedSeq[A]]
@@ -13,6 +13,16 @@ trait IndexedSeqOps[+A, +CC[X] <: IndexedSeq[X], +C] extends Any with SeqOps[A,
 
   def iterator(): Iterator[A] = view.iterator()
 
+  override def reverseIterator(): Iterator[A] = new AbstractIterator[A] {
+    private var i = self.length
+    def hasNext: Boolean = 0 < i
+    def next(): A =
+      if (0 < i) {
+        i -= 1
+        self(i)
+      } else Iterator.empty.next()
+  }
+
   override def view: IndexedView[A] = new IndexedView[A] {
     def length: Int = self.length
     def apply(i: Int): A = self(i)

collections/src/main/scala/strawman/collection/immutable/Vector.scala

@@ -94,16 +94,6 @@ final class Vector[+A] private[immutable] (private[collection] val startIndex: I
     s
   }
 
-  override def reverseIterator(): Iterator[A] = new Iterator[A] {
-    private var i = self.length
-    def hasNext: Boolean = 0 < i
-    def next(): A =
-      if (0 < i) {
-        i -= 1
-        self(i)
-      } else Iterator.empty.next()
-  }
-
   // Ideally, clients will inline calls to map all the way down, including the iterator/builder methods.
   // In principle, escape analysis could even remove the iterator/builder allocations and do it
   // with local variables exclusively. But we're not quite there yet ...