Hitting "Cannot read property 'body' of null" with "no-useless-constructor: off"

[gyzerok]

Hello everyone!

I seem to be hitting issue similar to #420 even though in my config no-useless-constructor rule is switched off as recommended.

Have no idea of how to debug/fix it myself, so I am kindly asking for your help. Thank you in advance!

What code were you trying to parse?

  export class BranchEvent {
    constructor(name: string, items: any, params?: Object)
    logEvent: () => void
  }

What did you expect to happen?
File to be linted

What actually happened?
An error was thrown

Versions

package	version
@typescript-eslint/parser	2.22.0
TypeScript	3.8.3
ESLint	6.8.0
node	13.8.0
yarn	1.17.3

In my .eslintrc.js I have

"no-useless-constructor": "off",
"@typescript-eslint/no-useless-constructor": "warn",

ESLint debug information

./node_modules/.bin/eslint "./src/declarations.d.ts" --debug
  eslint:cli CLI args: [ './src/declarations.d.ts', '--debug' ] +0ms
  eslint:cli Running on files +3ms
  eslint:config-array-factory Loading JSON config file: /path-to-my-project/package.json +0ms
  eslint:ignore-pattern Create with: [ IgnorePattern { patterns: [ '/node_modules/*', '/bower_components/*' ], basePath: '/path-to-my-project', loose: false } ] +0ms
  eslint:ignore-pattern   processed: { basePath: '/path-to-my-project', patterns: [ '/node_modules/*', '/bower_components/*' ] } +1ms
  eslint:ignore-pattern Create with: [ IgnorePattern { patterns: [ '/node_modules/*', '/bower_components/*' ], basePath: '/path-to-my-project', loose: false } ] +1ms
  eslint:ignore-pattern   processed: { basePath: '/path-to-my-project', patterns: [ '/node_modules/*', '/bower_components/*' ] } +0ms
  eslint:file-enumerator Start to iterate files: [ './src/declarations.d.ts' ] +0ms
  eslint:file-enumerator File: /path-to-my-project/src/declarations.d.ts +0ms
  eslint:cascading-config-array-factory Load config files for /path-to-my-project/src. +0ms
  eslint:cascading-config-array-factory No cache found: /path-to-my-project/src. +1ms
  eslint:config-array-factory Config file not found on /path-to-my-project/src +5ms
  eslint:cascading-config-array-factory No cache found: /path-to-my-project. +0ms
  eslint:config-array-factory Loading JS config file: /path-to-my-project/.eslintrc.js +0ms
  eslint:config-array-factory Config file found: /path-to-my-project/.eslintrc.js +2ms
  eslint:config-array-factory Loading parser "@typescript-eslint/parser" from /path-to-my-project/.eslintrc.js +0ms
  eslint:config-array-factory Loaded: @typescript-eslint/parser@2.22.0 (/path-to-my-project/node_modules/@typescript-eslint/parser/dist/parser.js) +1ms
  eslint:config-array-factory Loading plugin "@typescript-eslint" from /path-to-my-project/.eslintrc.js +147ms
  eslint:config-array-factory Loaded: @typescript-eslint/eslint-plugin@2.22.0 (/path-to-my-project/node_modules/@typescript-eslint/eslint-plugin/dist/index.js) +1ms
  eslint:config-array-factory Plugin /path-to-my-project/node_modules/@typescript-eslint/eslint-plugin/dist/index.js loaded in: 82ms +82ms
  eslint:config-array-factory Loading plugin "react" from /path-to-my-project/.eslintrc.js +0ms
  eslint:config-array-factory Loaded: eslint-plugin-react@7.19.0 (/path-to-my-project/node_modules/eslint-plugin-react/index.js) +1ms
  eslint:config-array-factory Plugin /path-to-my-project/node_modules/eslint-plugin-react/index.js loaded in: 124ms +124ms
  eslint:config-array-factory Loading plugin "react-hooks" from /path-to-my-project/.eslintrc.js +0ms
  eslint:config-array-factory Loaded: eslint-plugin-react-hooks@2.5.0 (/path-to-my-project/node_modules/eslint-plugin-react-hooks/index.js) +1ms
  eslint:config-array-factory Plugin /path-to-my-project/node_modules/eslint-plugin-react-hooks/index.js loaded in: 0ms +0ms
  eslint:cascading-config-array-factory Stop traversing because of 'root:true'. +360ms
  eslint:rules Loading rule 'default-case' (remaining=274) +0ms
  eslint:rules Loading rule 'no-dupe-class-members' (remaining=273) +1ms
  eslint:rules Loading rule 'no-undef' (remaining=272) +1ms
  eslint:rules Loading rule 'no-array-constructor' (remaining=271) +2ms
  eslint:rules Loading rule 'no-use-before-define' (remaining=270) +0ms
  eslint:rules Loading rule 'no-unused-expressions' (remaining=269) +3ms
  eslint:rules Loading rule 'no-unused-vars' (remaining=268) +0ms
  eslint:rules Loading rule 'no-useless-constructor' (remaining=267) +2ms
  eslint:rules Loading rule 'array-callback-return' (remaining=266) +0ms
  eslint:rules Loading rule 'dot-location' (remaining=265) +1ms
  eslint:rules Loading rule 'eqeqeq' (remaining=264) +1ms
  eslint:rules Loading rule 'new-parens' (remaining=263) +1ms
  eslint:rules Loading rule 'no-caller' (remaining=262) +1ms
  eslint:rules Loading rule 'no-cond-assign' (remaining=261) +0ms
  eslint:rules Loading rule 'no-const-assign' (remaining=260) +1ms
  eslint:rules Loading rule 'no-control-regex' (remaining=259) +0ms
  eslint:rules Loading rule 'no-delete-var' (remaining=258) +2ms
  eslint:rules Loading rule 'no-dupe-args' (remaining=257) +1ms
  eslint:rules Loading rule 'no-dupe-keys' (remaining=256) +1ms
  eslint:rules Loading rule 'no-duplicate-case' (remaining=255) +0ms
  eslint:rules Loading rule 'no-empty-character-class' (remaining=254) +1ms
  eslint:rules Loading rule 'no-empty-pattern' (remaining=253) +2ms
  eslint:rules Loading rule 'no-eval' (remaining=252) +2ms
  eslint:rules Loading rule 'no-ex-assign' (remaining=251) +1ms
  eslint:rules Loading rule 'no-extend-native' (remaining=250) +1ms
  eslint:rules Loading rule 'no-extra-bind' (remaining=249) +1ms
  eslint:rules Loading rule 'no-extra-label' (remaining=248) +0ms
  eslint:rules Loading rule 'no-fallthrough' (remaining=247) +1ms
  eslint:rules Loading rule 'no-func-assign' (remaining=246) +0ms
  eslint:rules Loading rule 'no-implied-eval' (remaining=245) +1ms
  eslint:rules Loading rule 'no-invalid-regexp' (remaining=244) +0ms
  eslint:rules Loading rule 'no-iterator' (remaining=243) +1ms
  eslint:rules Loading rule 'no-label-var' (remaining=242) +0ms
  eslint:rules Loading rule 'no-labels' (remaining=241) +1ms
  eslint:rules Loading rule 'no-lone-blocks' (remaining=240) +0ms
  eslint:rules Loading rule 'no-loop-func' (remaining=239) +1ms
  eslint:rules Loading rule 'no-mixed-operators' (remaining=238) +0ms
  eslint:rules Loading rule 'no-multi-str' (remaining=237) +2ms
  eslint:rules Loading rule 'no-native-reassign' (remaining=236) +1ms
  eslint:rules Loading rule 'no-negated-in-lhs' (remaining=235) +0ms
  eslint:rules Loading rule 'no-new-func' (remaining=234) +0ms
  eslint:rules Loading rule 'no-new-object' (remaining=233) +1ms
  eslint:rules Loading rule 'no-new-symbol' (remaining=232) +0ms
  eslint:rules Loading rule 'no-new-wrappers' (remaining=231) +0ms
  eslint:rules Loading rule 'no-obj-calls' (remaining=230) +1ms
  eslint:rules Loading rule 'no-octal' (remaining=229) +1ms
  eslint:rules Loading rule 'no-octal-escape' (remaining=228) +0ms
  eslint:rules Loading rule 'no-regex-spaces' (remaining=227) +1ms
  eslint:rules Loading rule 'no-restricted-syntax' (remaining=226) +3ms
  eslint:rules Loading rule 'no-script-url' (remaining=225) +2ms
  eslint:rules Loading rule 'no-self-assign' (remaining=224) +0ms
  eslint:rules Loading rule 'no-self-compare' (remaining=223) +1ms
  eslint:rules Loading rule 'no-sequences' (remaining=222) +0ms
  eslint:rules Loading rule 'no-shadow-restricted-names' (remaining=221) +1ms
  eslint:rules Loading rule 'no-sparse-arrays' (remaining=220) +0ms
  eslint:rules Loading rule 'no-template-curly-in-string' (remaining=219) +0ms
  eslint:rules Loading rule 'no-this-before-super' (remaining=218) +0ms
  eslint:rules Loading rule 'no-throw-literal' (remaining=217) +1ms
  eslint:rules Loading rule 'no-unreachable' (remaining=216) +0ms
  eslint:rules Loading rule 'no-unused-labels' (remaining=215) +0ms
  eslint:rules Loading rule 'no-useless-computed-key' (remaining=214) +1ms
  eslint:rules Loading rule 'no-useless-concat' (remaining=213) +0ms
  eslint:rules Loading rule 'no-useless-escape' (remaining=212) +1ms
  eslint:rules Loading rule 'no-useless-rename' (remaining=211) +0ms
  eslint:rules Loading rule 'no-with' (remaining=210) +1ms
  eslint:rules Loading rule 'no-whitespace-before-property' (remaining=209) +1ms
  eslint:rules Loading rule 'require-yield' (remaining=208) +1ms
  eslint:rules Loading rule 'rest-spread-spacing' (remaining=207) +0ms
  eslint:rules Loading rule 'strict' (remaining=206) +1ms
  eslint:rules Loading rule 'unicode-bom' (remaining=205) +0ms
  eslint:rules Loading rule 'use-isnan' (remaining=204) +1ms
  eslint:rules Loading rule 'valid-typeof' (remaining=203) +1ms
  eslint:rules Loading rule 'getter-return' (remaining=202) +1ms
  eslint:cascading-config-array-factory Configuration was determined: ConfigArray(2) [ { name: 'DefaultIgnorePattern', filePath: '', criteria: null, env: undefined, globals: undefined, ignorePattern: IgnorePattern { patterns: [Array], basePath: '/path-to-my-project', loose: false }, noInlineConfig: undefined, parser: undefined, parserOptions: undefined, plugins: undefined, processor: undefined, reportUnusedDisableDirectives: undefined, root: undefined, rules: undefined, settings: undefined }, { name: '.eslintrc.js', filePath: '/path-to-my-project/.eslintrc.js', criteria: null, env: { es6: true }, globals: { __DEV__: true, __dirname: false, __fbBatchedBridgeConfig: false, alert: false, cancelAnimationFrame: false, cancelIdleCallback: false, clearImmediate: true, clearInterval: false, clearTimeout: false, console: false, document: false, ErrorUtils: false, escape: false, Event: false, EventTarget: false, exports: false, fetch: false, FormData: false, global: false, Headers: false, Intl: false, Map: true, module: false, navigator: false, process: false, Promise: true, requestAnimationFrame: true, requestIdleCallback: true, require: false, Set: true, setImmediate: true, setInterval: false, setTimeout: false, URL: false, URLSearchParams: false, WebSocket: true, window: false, XMLHttpRequest: false }, ignorePattern: IgnorePattern { patterns: [Array], basePath: '/path-to-my-project', loose: false }, noInlineConfig: undefined, parser: { error: null, filePath: '/path-to-my-project/node_modules/@typescript-eslint/parser/dist/parser.js', id: '@typescript-eslint/parser', importerName: '.eslintrc.js', importerPath: '/path-to-my-project/.eslintrc.js' }, parserOptions: { ecmaVersion: 2018, sourceType: 'module', ecmaFeatures: [Object], warnOnUnsupportedTypeScriptVersion: true }, plugins: { '@typescript-eslint': [Object], react: [Object], 'react-hooks': [Object] }, processor: undefined, reportUnusedDisableDirectives: undefined, root: true, rules: { 'default-case': [Array], 'no-dupe-class-members': 'warn', 'no-undef': 'error', '@typescript-eslint/consistent-type-assertions': 'warn', 'no-array-constructor': 'warn', '@typescript-eslint/no-array-constructor': 'warn', 'no-use-before-define': [Array], '@typescript-eslint/no-use-before-define': [Array], 'no-unused-expressions': [Array], '@typescript-eslint/no-unused-expressions': [Array], 'no-unused-vars': [Array], '@typescript-eslint/no-unused-vars': [Array], 'no-useless-constructor': 'warn', '@typescript-eslint/no-useless-constructor': 'warn', 'array-callback-return': 'warn', 'dot-location': [Array], eqeqeq: [Array], 'new-parens': 'warn', 'no-caller': 'warn', 'no-cond-assign': [Array], 'no-const-assign': 'warn', 'no-control-regex': 'warn', 'no-delete-var': 'warn', 'no-dupe-args': 'warn', 'no-dupe-keys': 'warn', 'no-duplicate-case': 'warn', 'no-empty-character-class': 'warn', 'no-empty-pattern': 'warn', 'no-eval': 'warn', 'no-ex-assign': 'warn', 'no-extend-native': 'warn', 'no-extra-bind': 'warn', 'no-extra-label': 'warn', 'no-fallthrough': 'warn', 'no-func-assign': 'warn', 'no-implied-eval': 'warn', 'no-invalid-regexp': 'warn', 'no-iterator': 'warn', 'no-label-var': 'warn', 'no-labels': [Array], 'no-lone-blocks': 'warn', 'no-loop-func': 'warn', 'no-mixed-operators': [Array], 'no-multi-str': 'warn', 'no-native-reassign': 'warn', 'no-negated-in-lhs': 'warn', 'no-new-func': 'warn', 'no-new-object': 'warn', 'no-new-symbol': 'warn', 'no-new-wrappers': 'warn', 'no-obj-calls': 'warn', 'no-octal': 'warn', 'no-octal-escape': 'warn', 'no-regex-spaces': 'warn', 'no-restricted-syntax': [Array], 'no-script-url': 'warn', 'no-self-assign': 'warn', 'no-self-compare': 'warn', 'no-sequences': 'warn', 'no-shadow-restricted-names': 'warn', 'no-sparse-arrays': 'warn', 'no-template-curly-in-string': 'warn', 'no-this-before-super': 'warn', 'no-throw-literal': 'warn', 'no-unreachable': 'warn', 'no-unused-labels': 'warn', 'no-useless-computed-key': 'warn', 'no-useless-concat': 'warn', 'no-useless-escape': 'warn', 'no-useless-rename': [Array], 'no-with': 'warn', 'no-whitespace-before-property': 'warn', 'react-hooks/exhaustive-deps': 'warn', 'require-yield': 'warn', 'rest-spread-spacing': [Array], strict: [Array], 'unicode-bom': [Array], 'use-isnan': 'warn', 'valid-typeof': 'warn', 'getter-return': 'warn', 'react/forbid-foreign-prop-types': [Array], 'react/jsx-no-comment-textnodes': 'warn', 'react/jsx-no-duplicate-props': 'warn', 'react/jsx-no-target-blank': 'warn', 'react/jsx-no-undef': 'error', 'react/jsx-pascal-case': [Array], 'react/jsx-uses-react': 'warn', 'react/jsx-uses-vars': 'warn', 'react/no-danger-with-children': 'warn', 'react/no-direct-mutation-state': 'warn', 'react/no-is-mounted': 'warn', 'react/no-typos': 'error', 'react/react-in-jsx-scope': 'error', 'react/require-render-return': 'error', 'react/style-prop-object': 'warn', 'react-hooks/rules-of-hooks': 'error' }, settings: { react: [Object] } } ] on /path-to-my-project/src +60ms
  eslint:ignore-pattern Create with: [ IgnorePattern { patterns: [ '/node_modules/*', '/bower_components/*' ], basePath: '/path-to-my-project', loose: false }, IgnorePattern { patterns: [ './src/IOModels/**/*.*' ], basePath: '/path-to-my-project', loose: false } ] +424ms
  eslint:ignore-pattern   processed: { basePath: '/path-to-my-project', patterns: [ '/node_modules/*', '/bower_components/*', './src/IOModels/**/*.*' ] } +1ms
  eslint:ignore-pattern Check {
  filePath: '/path-to-my-project/src/declarations.d.ts',
  dot: false,
  relativePath: 'src/declarations.d.ts',
  result: false
} +1ms
  eslint:cli-engine Lint /path-to-my-project/src/declarations.d.ts +0ms
  eslint:linter Linting code for /path-to-my-project/src/declarations.d.ts (pass 1) +0ms
  eslint:linter Verify +0ms
  eslint:linter With ConfigArray: /path-to-my-project/src/declarations.d.ts +0ms
  eslint:linter An error occurred while traversing +60ms
  eslint:linter Filename: /path-to-my-project/src/declarations.d.ts +0ms
  eslint:linter Line: 47 +0ms
  eslint:linter Parser Options: {
  ecmaVersion: 9,
  sourceType: 'module',
  ecmaFeatures: { jsx: true, globalReturn: false },
  warnOnUnsupportedTypeScriptVersion: true
} +1ms
  eslint:linter Parser Path: /path-to-my-project/node_modules/@typescript-eslint/parser/dist/parser.js +0ms
  eslint:linter Settings: { react: { version: 'detect' } } +0ms
TypeError: Cannot read property 'body' of null

[bradzacher]

There's this big long line a dozen or so above the error in your debug logs

eslint:cascading-config-array-factory Configuration was determined: ConfigArray(2) [ { name: 'DefaultIgnorePattern', filePath: '', criteria: null, env: undefined, globals: undefined, ignorePattern: IgnorePattern { patterns: [Array], basePath: '/path-to-my-project', loose: false }, noInlineConfig: undefined, parser: undefined, parserOptions: undefined, plugins: undefined, processor: undefined, reportUnusedDisableDirectives: undefined, root: undefined, rules: undefined, settings: undefined }, { name: '.eslintrc.js', filePath: '/path-to-my-project/.eslintrc.js', criteria: null, env: { es6: true }, globals: { __DEV__: true, __dirname: false, __fbBatchedBridgeConfig: false, alert: false, cancelAnimationFrame: false, cancelIdleCallback: false, clearImmediate: true, clearInterval: false, clearTimeout: false, console: false, document: false, ErrorUtils: false, escape: false, Event: false, EventTarget: false, exports: false, fetch: false, FormData: false, global: false, Headers: false, Intl: false, Map: true, module: false, navigator: false, process: false, Promise: true, requestAnimationFrame: true, requestIdleCallback: true, require: false, Set: true, setImmediate: true, setInterval: false, setTimeout: false, URL: false, URLSearchParams: false, WebSocket: true, window: false, XMLHttpRequest: false }, ignorePattern: IgnorePattern { patterns: [Array], basePath: '/path-to-my-project', loose: false }, noInlineConfig: undefined, parser: { error: null, filePath: '/path-to-my-project/node_modules/@typescript-eslint/parser/dist/parser.js', id: '@typescript-eslint/parser', importerName: '.eslintrc.js', importerPath: '/path-to-my-project/.eslintrc.js' }, parserOptions: { ecmaVersion: 2018, sourceType: 'module', ecmaFeatures: [Object], warnOnUnsupportedTypeScriptVersion: true }, plugins: { '@typescript-eslint': [Object], react: [Object], 'react-hooks': [Object] }, processor: undefined, reportUnusedDisableDirectives: undefined, root: true, rules: { 'default-case': [Array], 'no-dupe-class-members': 'warn', 'no-undef': 'error', '@typescript-eslint/consistent-type-assertions': 'warn', 'no-array-constructor': 'warn', '@typescript-eslint/no-array-constructor': 'warn', 'no-use-before-define': [Array], '@typescript-eslint/no-use-before-define': [Array], 'no-unused-expressions': [Array], '@typescript-eslint/no-unused-expressions': [Array], 'no-unused-vars': [Array], '@typescript-eslint/no-unused-vars': [Array], 'no-useless-constructor': 'warn', '@typescript-eslint/no-useless-constructor': 'warn', 'array-callback-return': 'warn', 'dot-location': [Array], eqeqeq: [Array], 'new-parens': 'warn', 'no-caller': 'warn', 'no-cond-assign': [Array], 'no-const-assign': 'warn', 'no-control-regex': 'warn', 'no-delete-var': 'warn', 'no-dupe-args': 'warn', 'no-dupe-keys': 'warn', 'no-duplicate-case': 'warn', 'no-empty-character-class': 'warn', 'no-empty-pattern': 'warn', 'no-eval': 'warn', 'no-ex-assign': 'warn', 'no-extend-native': 'warn', 'no-extra-bind': 'warn', 'no-extra-label': 'warn', 'no-fallthrough': 'warn', 'no-func-assign': 'warn', 'no-implied-eval': 'warn', 'no-invalid-regexp': 'warn', 'no-iterator': 'warn', 'no-label-var': 'warn', 'no-labels': [Array], 'no-lone-blocks': 'warn', 'no-loop-func': 'warn', 'no-mixed-operators': [Array], 'no-multi-str': 'warn', 'no-native-reassign': 'warn', 'no-negated-in-lhs': 'warn', 'no-new-func': 'warn', 'no-new-object': 'warn', 'no-new-symbol': 'warn', 'no-new-wrappers': 'warn', 'no-obj-calls': 'warn', 'no-octal': 'warn', 'no-octal-escape': 'warn', 'no-regex-spaces': 'warn', 'no-restricted-syntax': [Array], 'no-script-url': 'warn', 'no-self-assign': 'warn', 'no-self-compare': 'warn', 'no-sequences': 'warn', 'no-shadow-restricted-names': 'warn', 'no-sparse-arrays': 'warn', 'no-template-curly-in-string': 'warn', 'no-this-before-super': 'warn', 'no-throw-literal': 'warn', 'no-unreachable': 'warn', 'no-unused-labels': 'warn', 'no-useless-computed-key': 'warn', 'no-useless-concat': 'warn', 'no-useless-escape': 'warn', 'no-useless-rename': [Array], 'no-with': 'warn', 'no-whitespace-before-property': 'warn', 'react-hooks/exhaustive-deps': 'warn', 'require-yield': 'warn', 'rest-spread-spacing': [Array], strict: [Array], 'unicode-bom': [Array], 'use-isnan': 'warn', 'valid-typeof': 'warn', 'getter-return': 'warn', 'react/forbid-foreign-prop-types': [Array], 'react/jsx-no-comment-textnodes': 'warn', 'react/jsx-no-duplicate-props': 'warn', 'react/jsx-no-target-blank': 'warn', 'react/jsx-no-undef': 'error', 'react/jsx-pascal-case': [Array], 'react/jsx-uses-react': 'warn', 'react/jsx-uses-vars': 'warn', 'react/no-danger-with-children': 'warn', 'react/no-direct-mutation-state': 'warn', 'react/no-is-mounted': 'warn', 'react/no-typos': 'error', 'react/react-in-jsx-scope': 'error', 'react/require-render-return': 'error', 'react/style-prop-object': 'warn', 'react-hooks/rules-of-hooks': 'error' }, settings: { react: [Object] } } ] on /path-to-my-project/src +60ms

The important bit of the line is

'no-useless-constructor': 'warn', '@typescript-eslint/no-useless-constructor': 'warn',

So something in your environment is turning the rule back on.
This suggests that either:

• you have another config files in your tree at or above the file being linted
• you have an overrides setting which is overriding something.
• your config isn't as you expect.

two things you can do:

1. provide your full ESLint RC. Hard for me to tell what's happening without it.
2. try running yarn eslint --print-config packages/eslint-plugin/src/index.ts --debug

This command will do 2 things; it'll dump the exact config that's used for the broken file, and it'll dump the minimal set of logs which describe how the config is loaded.

You can look for debug lines like the following to figure out what config files are used.
eslint:config-array-factory Loading JS config file:
eslint:config-array-factory Loading JSON config file:

[gyzerok]

Thank you very much @bradzacher for help!

After running yarn eslint --print-config packages/eslint-plugin/src/index.ts --debug I was able to identify the problem: the rule was redefined later in the file.

It was stupid of me not to check that in the first place, I am sorry 😅