You're again asserting thread unsafe mutations as a reason. It is not. Or if it is Kotlin is just wrong. Guarding against null in an unsafe thread race is point

You're again asserting thread unsafe mutations as a reason. It is not. Or if it is Kotlin is just wrong. Guarding against null in an unsafe thread race is pointless to the extreme. That didn't fix anything. It's pointless to complain about it ever. It's a wrong error in that fixing the error doesn't fix the bug in the code. There is no possibility of any kind that my snippet is null-unsafe exclusively. My code is null-safe in all situations where the resulting behavior is also correct. And the compiler could trivially prove that. If they wanted to actually take a stab at compiler-audited thread safety they should add some annotations or such to mark what is guarded by what. Otherwise the only reasonable assumption is to assume thread-compatible. Which my code also runs correctly in.