--- old/src/jdk.compiler/share/classes/com/sun/source/util/TreeScanner.java	2020-07-23 09:48:42.564713999 -0700
+++ new/src/jdk.compiler/share/classes/com/sun/source/util/TreeScanner.java	2020-07-23 09:48:42.100945982 -0700
@@ -75,6 +75,10 @@
  * @since 1.6
  */
 public class TreeScanner<R,P> implements TreeVisitor<R,P> {
+    /**
+     * Constructor for subclasses to call.
+     */
+    public TreeScanner() {}
 
     /**
      * Scans a single node.