False positive in `prefer-rest-params` when checking arguments.length

ESLint version: 2.8.0

What parser are you using?

    "parserOptions": {
        "ecmaVersion": 6,
        "sourceType": "module",
        "ecmaFeatures": {"jsx": true},
    },

When linting this code:

function makeTree(rootPath, branches) {
    console.assert(arguments.length === 2);
    console.assert(_.isArray(rootPath));
    console.assert(_.isArray(branches) && _.isArray(branches[0]));
    return _.map(branches, branch => rootPath.concat(branch));
}

I get this warning:

Use the rest parameters instead of 'arguments'  prefer-rest-params

I believe this to be a false positive. Imho just checking arguments.length should be an exception to this rule (possibly configurable).

[mysticatea]

It seems reasonable to me. Also, this is a relaxing enhancement, so this is a minor fix.

I will champion this.

[mikesherov]

Right, I agree @mik01aj but the rule is about prefering rest parameters over arguments, so erroring on using arguments other than as a parameter shouldn’t cause an issue.