private static @Nullable GrReferenceExpression getReferenceExpression(GrExpression expression) {
    if (expression instanceof GrMethodCallExpression) {
      expression = ((GrMethodCallExpression)expression).getInvokedExpression();
    }
    return expression instanceof GrReferenceExpression ? (GrReferenceExpression)expression : null;
  }
private static @Nullable GrReferenceExpression getReferenceExpression(GrExpression expression)