Any ideas?

@curioustechizen Are you using the 1.1 EAP Kotlin plug-in in IDEA as well?

Yes I am. In both IDEA and Android Studio. I remember that because I had to explicitly enable the RC channel for updates :-)

That's odd, the plug-in should add the three

lib/kotlin*jar

files with the correct version.

What I do not understand is - why can Gradle compile and run my code while the IDE cannot? Doesn't the IDE use Gradle under the covers?

exactly what a "compiler" is to an IDE is nebulous, you can bet the kotlin plugin does a hell of a lot more than simply generate code. It sounds like your compilation tool chain is on 1.1 RC and the kotliin plugin is on 1.0. If you go to tools -> kotlin -> configure kotlin updates, which update channel are you on? If your switching between versions of the plugin --and IDEA has been pushing several updates, you also might need to flush IDEA's AST cache, you can do that by clicking file -> invalidate caches & restart

Invalidate caches did not work. I mean, I no longer see compile errors but I do see the "Cannot add jps/kotlin-jps-plugin.jar from plugin 'Kotlin' to external compiler classpath: home directory of plugin not found" message in the event log plus, I expect a test to fail but it still passes. I'm still digging into this