arrow-body-style autofix errors with sequence expression

[mdjermanovic]

Tell us about your environment

• ESLint Version: 6.0.1 (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: {
    "arrow-body-style": "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.

First example:

const foo = () => { return bar, baz; };

Second example:

const a = 1;
if (true) {
  let foo = () => { return bar, a; };
  console.log(a); // 1
}

eslint index.js --fix

What did you expect to happen?

Not a syntax error or changed semantics.

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

const foo = () => bar, baz; // SyntaxError: Missing initializer in const declaration

const a = 1;
if (true) {
  let foo = () => bar, a;
  console.log(a); // undefined
}

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

Yes

[g-plane]

Should we add parens at this case?

[mysticatea]

Thank you for your report.

I confirmed it: online demo

I agree that we should parenthesize the body in that case as same as () => { return { bar, baz }; } case.