Kotlin has !! to convert a nullable type to a non-null type when the programmer is sure the type system is wrong and would prefer to have a runtime failure instead. This crops up a LOT especially when working with existing Java code.
For example see this commit to Kotlin itself:
Pretty ugly. The !! doesn’t really add much, it’s just type system noise.
If Kotlin automatically added !! wherever assignments or returns happened and it was needed to make the code compile, the type system would still carry nullability information and a runtime exception would be thrown at the earliest possible point. The downside is the programmer might not notice they auto-coerced away the nullability and lose a chance to write explicit handling code. IntelliJ could compensate by simply highlighting the code with a nice pastel shade to indicate possible NPE points.