fix(eslint-plugin): [no-unused-vars-experimental] handle processable private accessors

[brn]

What is this PR?

If no-unused-vars-experimental rule found private get/set accessor in class, throw
Error: Unknown node with kind 162/163.
because of accessor is not treated correctly.

So this pr fix that problems.

Reproduce

package.json

{
  "name": "project",
  "version": "1.0.0",
  "description": "",
  "main": "",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@typescript-eslint/eslint-plugin": "^3.0.2",
    "@typescript-eslint/parser": "^3.0.2",
    "@typescript-eslint/typescript-estree": "^3.0.2",
    "eslint": "^7.1.0",
    "typescript": "^3.9.3"
  }
}

.eslintrc.js

module.exports = {
  root: true,
  plugins: ['@typescript-eslint'],
  rules: {
    '@typescript-eslint/no-unused-vars-experimental': [
      'error',
      {
        ignoreArgsIfArgsAfterAreUsed: true,
        ignoredNamesRegex: '^unused'
      }
    ]
  },
  parser: '@typescript-eslint/parser',
  parserOptions: {
    project: './tsconfig.json',
  }
}

Project structure

project +
        |
        + - package.json
        | 
        + - .eslintrc.js
        | 
        +- src
             |
             +- a.ts

a.ts

class Test {
  private get name() {
    return "test";
  }
}

Command

npx eslint --fix --max-warnings 0 'src/a.ts'

Error message

➜ npx eslint --fix --max-warnings 0 'src/a.ts'

Oops! Something went wrong! :(

ESLint: 7.1.0

Error: Unknown node with kind 163.
Occurred while linting /private/tmp/project/src/a.ts:1
    at handleIdentifier (/private/tmp/project/node_modules/@typescript-eslint/eslint-plugin/dist/rules/no-unused-vars-experimental.js:163:27)
    at /private/tmp/project/node_modules/@typescript-eslint/eslint-plugin/dist/rules/no-unused-vars-experimental.js:266:33
    at Array.forEach (<anonymous>)
    at Program:exit (/private/tmp/project/node_modules/@typescript-eslint/eslint-plugin/dist/rules/no-unused-vars-experimental.js:260:29)
    at /private/tmp/project/node_modules/eslint/lib/linter/safe-emitter.js:45:58
    at Array.forEach (<anonymous>)
    at Object.emit (/private/tmp/project/node_modules/eslint/lib/linter/safe-emitter.js:45:38)
    at NodeEventGenerator.applySelector (/private/tmp/project/node_modules/eslint/lib/linter/node-event-generator.js:254:26)
    at NodeEventGenerator.applySelectors (/private/tmp/project/node_modules/eslint/lib/linter/node-event-generator.js:283:22)
    at NodeEventGenerator.leaveNode (/private/tmp/project/node_modules/eslint/lib/linter/node-event-generator.js:306:14)

[typescript-eslint]

Thanks for the PR, @brn!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

---

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[bradzacher]

thanks!

[bradzacher]

sorry - could you please add a test case for this to ensure we don't have a regression in future?

[brn]

@bradzacher Oh, sorry I missed that. I wll add.

[bradzacher]

#1856 is being released in 4.0, so no-unused-vars-experimental is being deprecated.

As such, we won't be accepting fixes for the rule, and suggest moving to the non-experimental version.
Thanks for the PR!