src/jdk.compiler/share/classes/com/sun/tools/javac/comp/DeferredAttr.java

@@ -1116,15 +1116,15 @@
  
      /**
       * A special tree scanner that would only visit portions of a given tree.
       * The set of nodes visited by the scanner can be customized at construction-time.
       */
-     abstract static class FilterScanner extends com.sun.tools.javac.tree.TreeScanner {
+     public abstract static class FilterScanner extends com.sun.tools.javac.tree.TreeScanner {
  
          final Predicate<JCTree> treeFilter;
  
-         FilterScanner(final Set<JCTree.Tag> validTags) {
+         protected FilterScanner(final Set<JCTree.Tag> validTags) {
              this.treeFilter = t -> validTags.contains(t.getTag());
          }
  
          @Override
          public void scan(JCTree tree) {

@@ -1138,11 +1138,11 @@
          }
  
          /**
           * handler that is executed when a node has been discarded
           */
-         void skip(JCTree tree) {}
+         protected void skip(JCTree tree) {}
      }
  
      /**
       * A tree scanner suitable for visiting the target-type dependent nodes of
       * a given argument expression.