HTMLElement.rootElement is deprecated.

[penn-z]

The contents of atom-text-editor elements are no longer encapsulated
within a shadow DOM boundary. Please, stop using rootElement and access
the editor contents directly instead.

HTMLElement.rootElement (/Applications/Atom Beta.app/Contents/Resources/app.asar/src/text-editor-element.js:23:10)
HoverService._getFromShadowDom (/Users/penn/.atom/packages/atom-languageclient/dist/src/atom/HoverService.js:172:23)
HoverService._setupView (/Users/penn/.atom/packages/atom-languageclient/dist/src/atom/HoverService.js:62:39)
SafeSubscriber._next (/Users/penn/.atom/packages/atom-languageclient/node_modules/lodash/lodash.js:4968:19)
SafeSubscriber.__tryOrSetError (/Users/penn/.atom/packages/atom-languageclient/node_modules/rxjs/Subscriber.js:247:16)
SafeSubscriber.next (/Users/penn/.atom/packages/atom-languageclient/node_modules/rxjs/Subscriber.js:187:27)