code: private void normalizeNodeTypes(Node n) {
      normalizeBlocks(n);
  
      for (Node child = n.getFirstChild();
           child != null; child = child.getNext()) {
        // This pass is run during the CompilerTestCase validation, so this
        // parent pointer check serves as a more general check.
        checkState(child.getParent() == n);
  
        normalizeNodeTypes(child);
      }
    }
docs: Covert EXPR_VOID to EXPR_RESULT to simplify the rest of the code.