no-regex-spaces false positive in character class

[mdjermanovic]

Tell us about your environment

• ESLint Version: 6.3.0
• Node Version: 10.16.0
• npm Version: 6.9.0

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

default

Please show your full configuration:

Configuration

module.exports = {
  parserOptions: {
    ecmaVersion: 2015,
  }
};

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

Demo link

/*eslint no-regex-spaces: "error"*/

/[  ]/.test("2"); // false

eslint index.js

What did you expect to happen?

No errors from the no-regex-spaces rule.

What actually happened? Please include the actual, raw output from ESLint.

Error and invalid auto-fix to:

/*eslint no-regex-spaces: "error"*/

/[ {2}]/.test("2"); // true

Are you willing to submit a pull request to fix this bug?

Yes, I would love to try.

I guess this can't be solved properly without regexpp?

[mdjermanovic]

I'm working on this

[platinumazure]

Should this instead collapse down to one space and still report an error?

[mdjermanovic]

Should this instead collapse down to one space and still report an error?

That would be a correct fix indeed :)

Though I don't think that's the intention of this rule, looks to me more like a case for a rule that would target duplicate characters in [], and also report [ a ], [11], maybe even [\d1].