A modern programming language that makes developers happier.

kotlinlang

Hi all, I reported [KT-12518](<https://youtrack.jetbrains.com/issue/KT-12518>) regarding the ability for a method returning `T?` to override a method returning `T!` that overrides a method returning `T`. While changing this behavior is a breaking change, we discussed adding a compiler warning. I've got some time on my hands right now and was hoping I could make this contribution. I started looking through the repo and was sent here by the README. Is it okay that I'm working on this? Any suggestions?