4.14 breaks my eslint: Cannot read property 'type' of undefined

[chapati23]

Tell us about your environment

• ESLint Version:
  4.14

• Node Version:
  8.9.1 (tried 9.3.0 as well, same result)

• npm Version:
  5.6.0

What parser (default, Babel-ESLint, etc.) are you using?
babel-eslint 8.1.0

Please show your full configuration:

Configuration

module.exports = {
  parser: 'babel-eslint',
  parserOptions: {
    ecmaFeatures: {
      generators: true,
      experimentalObjectRestSpread: true
    },
    sourceType: 'module',
    allowImportExportEverywhere: false
  },
  extends: [
    'eslint:recommended',
    'plugin:css-modules/recommended',
    'plugin:flowtype/recommended',
    'plugin:import/errors',
    'plugin:import/warnings',
    'plugin:jest/recommended',
    'plugin:promise/recommended',
    'plugin:react/recommended',
    'plugin:react-ssr/all',
    'plugin:redux-saga/recommended',
    'plugin:security/recommended'
  ],
  plugins: [
    'compat',
    'css-modules',
    'flowtype',
    'jest',
    'prettier',
    'promise',
    'react',
    'react-ssr',
    'redux-saga',
    'security'
  ],
  settings: {
    flowtype: {
      onlyFilesWithFlowAnnotation: true
    },
    'import/resolver': {
      node: {
        extensions: ['.js', '.jsx', '.json', '.css'],
        paths: './src'
      }
    },
    polyfills: ['fetch', 'promises']
  },
  env: {
    browser: true,
    'jest/globals': true
  },
  globals: {
    __DEV__: true,
    __dirname: true,
    artifacts: true,
    afterEach: true,
    beforeEach: true,
    beforeAll: true,
    console: true,
    describe: true,
    xdescribe: true,
    document: true,
    expect: true,
    fetch: true,
    global: true,
    Intl: true,
    it: true,
    xit: true,
    jest: true,
    module: true,
    process: true,
    Promise: true,
    require: true,
    setTimeout: true,
    test: true,
    window: true
  },
  rules: Object.assign(
    {},
    cssModulesRules,
    compatRules,
    flowtypeRules,
    importRules,
    prettierRules,
    promiseRules,
    reactRules,
    securityRules,
    {
      /*
       * Deactivated because prettier takes care of this for us
       * https://eslint.org/docs/rules/arrow-body-style
       */
      'arrow-body-style': 'off',

      /*
       * require an empty line between class members
       * https://eslint.org/docs/rules/lines-between-class-members
       */
      'lines-between-class-members': ['error', 'always'],

      /*
       * enforce adding specific exceptions when using console.log()
       * so we don't forget any accidental console.logs in the code
       * https://eslint.org/docs/rules/no-console
       */
      'no-console': ['error', { allow: ['assert'] }],

      /*
       * don't allow the same variable name inside a given scope
       * https://eslint.org/docs/rules/no-shadow
       */
      'no-shadow': 'error',

      /*
       * require let or const instead of var
       * https://eslint.org/docs/rules/no-var
       */
      'no-var': 'error',

      'padding-line-between-statements': [
        'error',
        { blankLine: 'always', prev: 'class', next: '*' },
        { blankLine: 'always', prev: 'do', next: '*' },
        { blankLine: 'always', prev: '*', next: 'export' },
        { blankLine: 'always', prev: 'for', next: '*' },
        { blankLine: 'always', prev: 'if', next: '*' },
        { blankLine: 'always', prev: 'switch', next: '*' },
        { blankLine: 'always', prev: 'try', next: '*' },
        { blankLine: 'always', prev: 'while', next: '*' },
        { blankLine: 'always', prev: 'with', next: '*' }
      ],

      /*
       * if a let variable is never reassigned, use const instead of let
       * https://eslint.org/docs/rules/prefer-const
       */
      'prefer-const': 'error'
    }
  )
}

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

    if (format.second) {
      let seconds = moment.duration(remainingTime).get('seconds')
      seconds = seconds >= 0 ? seconds : 0
      if (leadingZero) {
        seconds = addLeadingZero(seconds)
      }
      html.push(
        <span className="react-cntdwn-second" key="second">
          {seconds}sec
        </span>
      )
    }

eslint --fix 'src/**/*.js'

What did you expect to happen?
Run eslint as usual

What actually happened? Please include the actual, raw output from ESLint.
eslint throws an error

Cannot read property 'type' of undefined
TypeError: Cannot read property 'type' of undefined
    at isForInRef (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/rules/no-unused-vars.js:410:24)
    at variable.references.some.ref (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/rules/no-unused-vars.js:447:21)
    at Array.some (<anonymous>)
    at isUsedVariable (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/rules/no-unused-vars.js:446:40)
    at collectUnusedVariables (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/rules/no-unused-vars.js:569:26)
    at collectUnusedVariables (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/rules/no-unused-vars.js:576:17)
    at Program:exit (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/rules/no-unused-vars.js:621:36)
    at listeners.(anonymous function).forEach.listener (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/util/safe-emitter.js:47:58)
    at Array.forEach (<anonymous>)
    at Object.emit (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/util/safe-emitter.js:47:38)
    at NodeEventGenerator.applySelector (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/util/node-event-generator.js:251:26)
    at NodeEventGenerator.applySelectors (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/util/node-event-generator.js:280:22)
    at NodeEventGenerator.leaveNode (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/util/node-event-generator.js:303:14)
    at CodePathAnalyzer.leaveNode (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/code-path-analysis/code-path-analyzer.js:630:23)
    at Traverser.leave [as _leave] (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/linter.js:1000:32)
    at Traverser._traverse (/Users/chapati/projects/brickblock/brickblock-ui/node_modules/eslint/lib/util/traverser.js:155:18)
error Command failed with exit code 1.

What could be the reason?
Reverting to 4.13 fixes the error for me so it must have been something introduced in 4.14
Maybe this one? 1c2aafd

[mysticatea]

Thank you for the report.

Would you confirm if it's duplicate of #9762 or #9767? (does it reproduce with babel-eslint@8.1.1?)

[chapati23]

thanks @mysticatea, just saw the patch to babel-eslint@8.1.1 came out today and indeed fixed this problem.

merry christmas :)