Fix and test case for #2276.

1 files changed, 4 insertions, 12 deletions

diff --git a/src/library/scala/xml/transform/BasicTransformer.scala b/src/library/scala/xml/transform/BasicTransformer.scala
index 917884617c..a79c32a5f0 100644
--- a/src/library/scala/xml/transform/BasicTransformer.scala
+++ b/src/library/scala/xml/transform/BasicTransformer.scala
@@ -25,7 +25,7 @@ abstract class BasicTransformer extends Function1[Node,Node]
    *  @return   ...
    */
   protected def unchanged(n: Node, ns: Seq[Node]) =
-    ns.length == 1 && (ns.head eq n)
+    ns.length == 1 && (ns.head == n)
 
   /** Call transform(Node) for each node in ns, append results
    *  to NodeBuffer.
@@ -37,18 +37,10 @@ abstract class BasicTransformer extends Function1[Node,Node]
    *  otherwise a new sequence of concatenated results.
    */
   def transform(ns: Seq[Node]): Seq[Node] = {
-    def testForChange(n: Node): Option[Seq[Node]] = {
-      val n2 = transform(n)
-      if (unchanged(n, n2)) None
-      else Some(n2)
-    }
-    // if any node is changed by the transform, concatenate
-    // the unchanged nodes with a recursive call.
-    for ((n, i) <- ns.zipWithIndex ; n2 <- testForChange(n))
-      return (ns take i) ++ transform(n2)
+    val (xs1, xs2) = ns span (n => unchanged(n, transform(n)))
 
-    // no change, return original sequence
-    ns
+    if (xs2.isEmpty) ns
+    else xs1 ++ transform(xs2.head) ++ transform(xs2.tail)
   }
 
   def transform(n: Node): Seq[Node] = {