SyntaxError: Invalid regular expression flag

I use
create-react-app with "react-scripts": "^2.1.5"
and "react-styleguidist": "^8.0.6"

Warning: Cannot parse src/components/Card/Card.jsx: SyntaxError: Invalid regular expression flag (1:8)

It usually means that react-docgen does not understand your source code, try to file an issue here:
https://github.com/reactjs/react-docgen/issues

import React from "react";
// nodejs library that concatenates classes
import classNames from "classnames";
// nodejs library to set properties for components
import PropTypes from "prop-types";
// @material-ui/core components
import withStyles from "@material-ui/core/styles/withStyles";
// @material-ui/icons

// core components
import cardStyle from "./cardStyle.jsx";

function Card({ ...props }) {
	const { classes, className, children, plain, carousel, ...rest } = props;
	const cardClasses = classNames({
		[classes.card]: true,
		[classes.cardPlain]: plain,
		[classes.cardCarousel]: carousel,
		[className]: className !== undefined
	});
	return (
		<div className={cardClasses} {...rest}>
			{children}
		</div>
	);
}

Card.propTypes = {
	classes: PropTypes.object.isRequired,
	className: PropTypes.string,
	plain: PropTypes.bool,
	carousel: PropTypes.bool,
	children: PropTypes.object.isRequired
};

export default withStyles(cardStyle)(Card);

and "react-styleguidist": "^8.0.6"
styleguide.config.js

module.exports = {
	propsParser: require("react-docgen").parse,
	webpackConfig: require("react-scripts/config/webpack.config"),
};

Start with Card/Card.jsx and styleguide.config.js, then run the reported react-docgen parse through the react-styleguidist setup. Reproduce the invalid regular expression flag error and trace which syntax construct causes it; done means the example parses successfully or the unsupported syntax is clearly identified and covered by an appropriate test.