Can't find the .klib file when migrating to KMP?

If you stumble upon an error while migrating a gradle module to KMP, where it complains when compiling that it can't find any code, and you strongly suspect of KT-52344...

Have you checked that your src/{sourceSet}/ is kotlin and not java? Because I didn't... and I was going insane.

src/commonMain/java was under my nose all the time. Just rename to src/commonMain/kotlin like it always should have been.

Anyway, I'm posting this junk because I'm pretty sure I'll stumble upon this again in the future, and hopefully I'll be schooled by myself.