!README.md

Code that reproduces the bug

Usage

yarn install
npx stylelint index.css

Actual

No error.

Expected

index.css
 5:1  ✖  .Component__root--unused is defined but doesn't match any elements in index.jsx.  plugin/no-unused-selectors

.gitignore

/node_modules
/yarn.lock

index.css

.Component__root {
  background: black;
}

.Component__root--unused {
  background: red;
}

index.jsx

import React from 'react';

const Component = () => {
  return <div className="Component__root"></div>;
};

export { Component };

package.json

{
  "private": "true",
  "devDependencies": {
    "stylelint": "14.8.5",
    "stylelint-no-unused-selectors": "1.0.40"
  }
}

stylelint.config.js

module.exports = {
  plugins: ['stylelint-no-unused-selectors'],
  rules: {
    'plugin/no-unused-selectors': {},
  },
};