why isn't this implicitly forced?

1. the compiler is pretty limited in what it tracks between variables for smart-casting, e.g. https://kotlinlang.org/spec/type-inference.html#bound-smart-casts 2. are you intentionally relying on invariance? if the declaration were

Type<out T>

then

doSomethingWithType<Any>(Type.OnlyWithString(""), Holder(0))

would be completely legal

Well the actual Type as is in our application is covariant (

out T

), but in general, I only want to be able to call doSomethingWithType if both Type and Holder have the exact same types

then you can't check that they're both the same without something like

data class HolderWithType(val type: String, val value: String) : Type<String>, Holder<String>

and using that instead

the use-case is, we're building search-criterias for our database where we have a searchCriteriaType (

IsLessThan<T : Comparable<T>>

,

IsNull<Nothing>

, etc.) and a path source from javax. For some of the criteriabuilder functions like the actual "greaterThan", the types of the path and expression need to have the same subtype. But for a

like

function, path needs to be string, so we setup a searchcriteria that only accepts strings as well

nope