[Bug]: @babel/eslint-parser using @babel/plugin-proposal-decorators errors on class fields with accessor keyword

[augustjk]

💻

• Would you like to work on a fix?

How are you using Babel?

@babel/eslint-parser

Input code

function logged(value, { kind, name }) {
  // implementation
}

class C {
  @logged accessor x = 1;
  //               ^ error  'x' is not defined  no-undef (eslint)
}

Configuration file name

babel.config.json

Configuration

{
  "plugins": [["@babel/plugin-proposal-decorators", { "version": "2023-05" }]]
}

Current and expected behavior

Stackblitz repro: https://stackblitz.com/edit/stackblitz-starters-jypgau?file=index.js

Notice that eslint command produces an error.

Expectation is to have no error as this is valid syntax.

The actual compilation with @babel/cli works properly and the output runs as expected.

Environment

  System:
    OS: Linux 5.0 undefined
  Binaries:
    Node: 18.18.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 9.4.2 - /usr/local/bin/npm
    pnpm: 8.6.12 - /usr/local/bin/pnpm
  npmPackages:
    @babel/cli: ^7.23.0 => 7.23.0 
    @babel/core: ^7.23.0 => 7.23.0 
    @babel/eslint-parser: ^7.22.15 => 7.22.15 
    @babel/plugin-proposal-decorators: ^7.23.0 => 7.23.0 
    eslint: ^8.50.0 => 8.50.0

Possible solution

No response

Additional context

No response

[babel-bot]

Hey @augustjk! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite.

[JLHwung]

The decorators syntax are stage 3 features, which is not supported by ESLint. ESLint only supports stage 4 features.

The @babel/eslint-parser enables ESLint to parse such syntax, but it does not guarantee that ESLint's rule actually work with the new syntax. The @babel/eslint-plugin is to enhance the ESLint rules so that they can work with the experimental syntax. Unfortunately the current @babel/eslint-plugin does not support the no-undef rule, so supporting accessors can be a feature request.