After downloading the latest version of Intellij and updating to the latest plugin I've had issues with test classes that have companion objects. On-screen feedback (failed compile, etc) does not work. Refactoring and other actions that apply to a class file do not work. For example, Ctrl-X does not do anything, rename does not work, etc. There is no option available to run the test in the context menu and there is no way to run the test from within Intellij because the file is not recognized as a test. Once I move all of the code out of the companion object or even just rename the object to be something else, then everything works again.