Library methods such as 'listOf' are resolved
to have the package fragments as their parents,
but JVM expects their containing file classes as parents.
This fix generates those file classes and
uses them as parent replacements for such library methods.
Don't insert implicit null check on a value of @EnhancedNullability type
used where @EnhancedNullability type is expected.
This uncovers a bunch of other problems in FE and BE.
KT-36343 and KT-36347 are bugs in StrictJavaNullabilityAssertions
implementation which should most likely be fixed in next major language
version (with proper breaking change notice).
KT-36344 is a design problem which should be addressed after 1.4 issues
are resolved.
Dmitriy Novozhilov