Tell us about your environment

• ESLint Version: 4.0.0
• Node Version: 8.0.0
• npm Version: 5.0.3

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

Please show your full configuration:

{
	"extends": "eslint:recommended",
	"parserOptions": {
		"ecmaVersion": 2017,
		"sourceType": "module",
		"ecmaFeatures": {
			"experimentalObjectRestSpread": true,
			"impliedStrict": true,
			"globalReturn": false,
			"jsx": true
		}
	},
	"parser": "babel-eslint"
}

What did you do? Please include the actual source code causing the issue.

class Foo {
    static bar = true

    baz = 'meh'
}

What did you expect to happen?
no errors.

What actually happened? Please include the actual, raw output from ESLint.
no-undef is treating bar and baz as errors (assigning new globals?) This didn't error in eslint 3.x.x