Fix TypeScript Autocomplete for RxJS Operators in WebStorm
I had the same issue, even with WebStorm 2016.2 (final). The solution that worked for me was in a comment to another answer, so to make it more visible, here it is as a proper answer:
Delete the .idea folder.
I did this, and then restarted WebStorm. Then all the rxjs definitions worked.
I'm using WebStorm 2016 and this helped me with my angular 2 + ionic 2 project:
WebStorm -> Preferences -> Languages & Frameworks -> JavaScript -> Libraries -> [Ensure 'ECMAScript 6' and 'your-progect/node_modules' are checked].then Apply -> Save -> Restart WebStorm
Turns out it was a problem with PhpStorm.
I reached out to Jetbrains support, and they suggested upgrading to version 2016.2 EAP (Early Access Program), which does fix the problem.