code: static boolean isNestedObjectPattern(Node n) {
      checkState(n.isObjectPattern());
      for (Node key = n.getFirstChild(); key != null; key = key.getNext()) {
        Node value = key.getFirstChild();
        if (value != null
            && (value.isObjectLit() || value.isArrayLit() || value.isDestructuringPattern())) {
          return true;
        }
      }
      return false;
    }
docs: Determine whether the destructuring object pattern is nested
  
  @param n object pattern node