Adding KModifier for interface type parameter.

[vnermolaev]

Hi!

Somewhere in the code, I have interfaces:

interface Base

interface BaseProvider {
    fun list(): List<out Base>
}

now using kotlin poet, I'd like to create an implementation of BaseProvider, but I am facing difficulties trying to specify the return type of list(), consider the following fragment:

List::class.parameterizedBy(
    Base::class  // <- how do I add a modifier KModifier.OUT 
)

One thing I tried is to "abuse" TypeVariableName as follows

List::class.asClassName().parameterizedBy(
    TypeVariableName(T::class.qualifiedName.toString(), KModifier.OUT)
)

but in this case, the modifier is stripped and the results of the two snippets are equivalent.

Is there a mechanism or a workaround to variance in such cases?

[Egorand]

What you're looking for is probably something along the lines of:

List::class.asClassName().parameterizedBy(
    WildcardTypeName.producerOf(Base::class.asTypeName())
)

[vnermolaev]

Thanks a lot! Unfortunately, this is not documented :(

[Egorand]

There is a mention of WildcardTypeName.producerOf in %T for Types, but please feel free to send us a PR if you have ideas on how to document it better.