Unable to run scala-xml 1.0.6 on 2.11.8

.travis.yml

@@ -4,6 +4,9 @@ scala: dummy # using crossScalaVersions over TRAVIS_SCALA_VERSION
 script:
  - cd sbt-sample
  - sbt +update
+ - sbt ++2.11.8 "runMain ExponentialTransformer"
+ - sbt ++2.12.0 "runMain ExponentialTransformer"
+ - sbt ++2.12.1 "runMain ExponentialTransformer"
  - cd -
  - cd maven-sample
  - mvn compile

sbt-sample/ExponentialTransformer.scala

@@ -0,0 +1,21 @@
+import scala.xml._
+
+object ExponentialTransformer extends App {
+
+    var i = 0
+    def translate(text: String): String = {
+        i += 1
+        return "!%s!".format(text)
+    }
+
+    val xmlNode = <a><b><c><h1>Hello Example</h1></c></b></a>
+
+    new transform.RuleTransformer(new transform.RewriteRule {
+        override def transform(n: Node): Seq[Node] = n match {
+            case t: Text if !t.text.trim.isEmpty => Text(translate(t.text.trim))
+            case _ => n
+        }
+    }).transform(xmlNode)
+
+    println(s"scala.xml.transform.RuleTransformer called $i time(s)")
+}