no-unused-vars error message should provide hint on ignorePattern.

We use no-unused-vars but provide allowed patterns for ignored vars and args.

"no-unused-vars": [1, {"vars": "all", varsIgnorePattern: "^_", "args": "all", "argsIgnorePattern": "^_"}],

With this code:

/* eslint no-unused-vars: [2, {"vars": "all", varsIgnorePattern: "^_", "args": "all", "argsIgnorePattern": "^_"}] */

[1,2,3].map((item, index, array) => {
  return item / array.length;
});

We get this error:

3:20 - 'index' is defined but never used. (no-unused-vars)

It is unreasonable for our engineers to be aware of our allowed pattern in the configuration and this warning will instead cause people to go through lots of work and confusion to get eslint to pass, or they will just turn it off.

I think a more valuable warning message would be something like this:

3:20 - 'index' is defined but never used. If this is intentional, consider matching the allowed unused argument pattern /^_/ (no-unused-vars)

[platinumazure]

@TheSavior We will accept the issue when enough people on the ESLint core team have supported the issue that we have reached consensus. This means one champion and three 👍s from other team members.

I’ll champion. So we need two more 👍s (mine no longer counts).

@eslint/eslint-team Anyone else want to support this? I think this would be a small but very useful improvement to the messaging for this rule.

[kaicataldo]

It looks like we missed the fixes message on the PR. This was closed in https://github.com/eslint/eslint/pull/9176.