ECMAFeature classes should throw when disabled

[emmenko]

I've noticed that if I use babel-eslint as parser, the ecmaFeatures.classes = false option does nothing.

Given this configuration

$ cat .eslintrc
/* http://eslint.org/docs/rules/ */
{
  "parser": "babel-eslint",
  "ecmaFeatures": {
    "classes": false
  },
  "env": {
    "node": true
  },
  "rules": {
    "eol-last": 2,
    "quotes": [2, "single"],
    "semi": 0,
    "strict": 0
  }
}

and this file

// test-class.js

class Foo {
  constructor() {
    this.foo = 'bar'
  }
}

When I run

$ eslint test-class.js
$ echo $?
0

When I remove the parser option it works

$ cat .eslintrc
/* http://eslint.org/docs/rules/ */
{
  "ecmaFeatures": {
    "classes": false
  },
  "env": {
    "node": true
  },
  "rules": {
    "eol-last": 2,
    "quotes": [2, "single"],
    "semi": 0,
    "strict": 0
  }
}

$ eslint test-class.js

test-class.js
  1:1  error  Unexpected reserved word

✖ 1 problem (1 error, 0 warnings)

Is this a problem with babel-eslint ?

[sebmck]

Nope, intended behaviour. Acorn does not currently support feature-specific flags.

[emmenko]

Woah, that was fast ;)

So what should I do? Do you have any suggestion or workaround?

[sebmck]

Can't really do anything about it.

[emmenko]

So that means that any ecmaFeatures option is ignored?

[sebmck]

Correct.

[emmenko]

Hmm ok so if want to forbid the use of class (or something else) I should create an eslint-plugin ?

[sebmck]

That's the only way, yes.

[emmenko]

Ok, at least I know how to proceed. Many thanks for the fastest support ever! ;)

[emmenko]

For who's interested, I'm creating a plugin to forbid class
https://github.com/emmenko/eslint-plugin-no-class