Question - Resolve the TypeName of a type argument with type arguments.

[callius]

The following is a class structure for example purposes:

interface Target<V> {
    val value: V 
}

interface TargetBuilder<I, T : Target<I>> {
    …
}

abstract class GenericTargetBuilder<I> : TargetBuilder<I, GenericTarget<I>> {
    …
}

class A : GenericTargetBuilder<Int>() {
    …
}

I would like to resolve GenericTarget<Int> from class A using kotlinpoet-ksp.

Following the docs, I tried the following:

1. I do a tree search on the super types of class A to find the first TypeReference of TargetBuilder.
2. At this point, I have the TypeReferences and TypeDeclarations of all the super types of class A.
3. I take the second type argument (index 1) of the TargetBuilder declaration on GenericTargetBuilder.
4. Now, I call toTypeName on the type argument type's TypeReference, passing in a recursive TypeParametersResolver (foldRight on all of the parent declarations’ type parameters, if any).

I get GenericTarget<I>, instead of the expected GenericTarget<Int>.

How should I go about resolving GenericTarget<Int> from this kind of class structure?

[callius]

I was able to solve my problem by calling toClassName and parameterizedBy, passing a list generated by recursively resolving each type parameter from the parent hierarchy by index.

Though, it would be nice to simply be able to use toTypeName for this.

[Egorand]

Are you interested in sending us a PR that adds the toTypeName method to cover this use case?

[callius]

@Egorand, possibly, although probably not any time soon.

However, in the time since this discussion was started, I published the library I had been working on which includes my aforementioned solution. If anyone comes across this thread and has some time on their hands, they are more than welcome to use it to create a PR.

My solution can be found here.

Thanks!