I'm looking at the code that I wrote before. There is cache:

val cache = MutableMap<String, Any?>

where value could be String, Int, Map, Array, etc. Then i retrieve values from it through the chain of functions, where caller is responsible to specify correct type.

cache[key] as R?

Question: what problems I may get with that approach? All of this code is internal to the module, and run on jvm/ios.

If the user messes up and they don't specify the right type you'll get a classcastexception.

It would be safer to use:

cache[key] as? R?

. That way wrong types would be ‘ignored’. The result would be null then.

Except then there's no difference between "not in the cache" and "programmer error"

thx, classcastexception is fine in this case

Although that exception will only occur when the generic code ends, so if for example people just put it in some other generic code the exception might not happen immediately.