--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/ir/visitor/NodeOperatorVisitor.java	Wed Jul 05 20:51:37 2017 +0200
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/ir/visitor/NodeOperatorVisitor.java	Mon Sep 28 08:40:39 2015 +0200
@@ -34,7 +34,7 @@
  * Like NodeVisitor but navigating further into operators.
  * @param <T> Lexical context class for this NodeOperatorVisitor
  */
-public class NodeOperatorVisitor<T extends LexicalContext> extends NodeVisitor<T> {
+public abstract class NodeOperatorVisitor<T extends LexicalContext> extends NodeVisitor<T> {
     /**
      * Constructor
      *