no-extra-parens ignores param and destructuring defaults

[mdjermanovic]

Tell us about your environment

• ESLint Version: 6.0.0 (same with 5.16.0)
• 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: 6,
  },
  rules: {
    "no-extra-parens": "error",
  }
};

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

function foo(a = (b)) {}

const bar = (a = (b)) => a;

const [a = (b)] = [];

const {c = (d)} = {};

eslint index.js

What did you expect to happen?

4 errors.

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

Nothing, no errors.

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

Yes, I'll do it.

Inner expressions are fine (e.g. ((b * c) + d)) would be reported), only the top level is missing.

Found this while working on #11848, the "AssignmentPattern" handler is missing. It should check its .right.

Just need help with the analysis:

comma operator ("SequenceExpression") inside should be checked for sure.

Is there any other case where these parens could be necessary?

[mysticatea]

Thank you for your report.

I confirmed it.