Deserialization Error Caused by Generic Sealed Interface

[CyanTachyon]

Describe the bug

I previously reported a bug. Simply put, when a class with generics has a field whose type is a generic interface, and the implementing class of the interface also has generics, it would cause an error.

It has been fixed, but there's still a slight change that causes errors:

import kotlinx.serialization.Serializable
import kotlinx.serialization.json.Json

@Serializable
sealed interface I<out T>

@Serializable
data class A<out T>(val x: T) : I<T>

@Serializable
data class B<out T>(val x: List<I<T>>)

/*
The B class from the previous issue:

@Serializable
data class B<out T>(val x: I<T>)

This can now be deserialized normally, but when changing I<T> to List<I<T>>, it fails again
 */

fun main()
{
    val a: I<Int> = A(42)
    val b: B<Int> = B(listOf(a))
    val json = Json { prettyPrint = true }
    val jsonB = json.encodeToString(b)

    // failed
    runCatching { json.decodeFromString<B<Int>>(jsonB) }.onFailure(Throwable::printStackTrace).onSuccess(::println)
}

Exception in thread "main" kotlinx.serialization.SerializationException: Serializer for subclass 'Int' is not found in the polymorphic scope of 'I'.
Check if class with serial name 'Int' exists and serializer is registered in a corresponding SerializersModule.
To be registered automatically, class 'Int' has to be '@Serializable', and the base class 'I' has to be sealed and '@Serializable'.

Expected behavior

no error and successful serialization

Environment

• Kotlin version: 2.2.10
• Library version: 1.9.0
• Kotlin platforms: JVM
• Gradle version: 8.11

[CyanTachyon]

Replacing List<I<T>> with similar constructs like Box<I<T>> still results in similar errors

@Serializable
data class Box<out T>(val value: T)