Languages (and their proponents) should not treat the end user (i.e. It's even worse when things just get dismissed as 'I feel like it's better' and then when you provide reasons people will say it's not normal. You could argue javac has some magic too, but not near as much and it's pretty well spelled out whereas you won't find the docs for all of these intrinsics.

I'm tired of being surprised by the bytecode that Kotlin generates. It's gotten to the point on my advanced JVM projects where I have to just drop into Java all the time to avoid this stuff, get the proper MethodHandle.invokeExact semantics, etc, etc. For example, I need to have as few instructions between a JNI call and the next line (I am starting a SingleStep JVMTI callback as part of my development on a fuzzer) and those intrinsics don't help. The benefit is you can insert a null check in one place which then propagates through the rest of your Kotlin (or Swift) code. The beauty of IUO is that you can ignore the nullability and you have the same amount of safety you have today: if you touch a null value you get an exception (or abort in Swift's case). There is no requirement to choose just one. It could even support all of the popular nullability annotations. The Kotlin compiler could treat every parameter and return value that doesn't have a nullability annotation as an implicitly unwrapped optional (Type!).

I presume it would be pretty challenging to provide a proper compatibility with Java, transforming all nullable Kotlin values to Optional and vice-versa, especially in such tight areas like Java reflection. To make a simpler mental picture, imagine Objective-C and Swift being connected side-by-side and Kotlin and Java as a stack, where Kotlin is on top. Apple uses a bridging mechanism to connect Objective-C and Swift binaries, when Kotlin uses the same bytecode as Java. >Unfortunately, it is not really possible to change Kotlin behave the same way.

Nullable kotlin