• Create vue 2 project using following config
  

• npm install

• add rules inside .eslintrc.cjs

  rules: {
      "@typescript-eslint/prefer-optional-chain": "error"
  }

• npm run lint

• terminal error

  Error: Error while loading rule '@typescript-eslint/prefer-optional-chain': You have used a rule which requires parserServices to be generated. You must therefore provide a value for the "parserOptions.project" property for @typescript-eslint/parser.

FYI.
Adding parserOptions: { project: ["tsconfig.json"] } to .eslintrc.cjs won't help.
Maybe caused by eslint-plugin-vue or @typescript-eslint