PhpStorm and JavaScript: I'm getting "Cannot find declaration to go to"

I'm playing with my simple NodeJS project in PhpStorm and suddenly the control-click navigation stopped working. When I click on a required file path, I just get message Cannot find declaration to go to. For example:

var Controller = require('./lib/Controller');

The file is definitely there as the program runs without problems. And if I control-click some global function or object (like "require" itself), the navigation works, the definition of the function/object is opened.

It affects now all my NodeJS/JavaScript projects. Is it possible that I simply disabled some kind of code analysis?

I have recently upgraded from PhpStorm 7 to EAP (to get grunt support) and then to 8.0.1. The problem appeared somewhere during the upgrades. I just can't tell exactly when.