I think you can make it feasible with a few features.
Not sure which of these kotlin has if any
1. declaring that a type isn’t null with ! appended.
2. Suppression annotations beatable at the file / class / function / line levels to disable the check
3. Facades / Decorators that can be added by anyone that tell the compiler retrofitted additional typing information on existing libraries (the defintely typed / typescript approach)
ad 1: `!` in kotlin actually mean "platform type that could be nullable or not". When you add !! to a value of that type, you declare it as non-nullable.
Not sure which of these kotlin has if any
1. declaring that a type isn’t null with ! appended.
2. Suppression annotations beatable at the file / class / function / line levels to disable the check
3. Facades / Decorators that can be added by anyone that tell the compiler retrofitted additional typing information on existing libraries (the defintely typed / typescript approach)