add "elementFinished" to RecursiveTreeElementWalkingVisitor

platform/core-impl/src/com/intellij/psi/impl/source/tree/RecursiveTreeElementWalkingVisitor.java

@@ -58,6 +58,7 @@ public abstract class RecursiveTreeElementWalkingVisitor extends TreeElementVisi
   private final WalkingState<ASTNode> myWalkingState = new WalkingState<ASTNode>(ASTTreeGuide.instance) {
     @Override
     public void elementFinished(@NotNull ASTNode element) {
+      RecursiveTreeElementWalkingVisitor.this.elementFinished(element);
     }
 
     @Override
@@ -66,6 +67,9 @@ public abstract class RecursiveTreeElementWalkingVisitor extends TreeElementVisi
     }
   };
 
+  protected void elementFinished(@NotNull ASTNode element) {
+  }
+
   @Override
   public void visitLeaf(LeafElement leaf) {
     visitNode(leaf);