Ktor client using KxS throws unhelpful error when trying to decode non-serializable class boxed in a generic container

[Kantis]

Given that I make any request that tries to decode something to a List<T>, where T is not serializable, Ktor-client will generate an error like this:

kotlinx.serialization.SerializationException: Serializer for class 'List' is not found.
Please ensure that class is marked as '@Serializable' and that the serialization compiler plugin is applied.

	at kotlinx.serialization.internal.Platform_commonKt.serializerNotRegistered(Platform.common.kt:90)
	at kotlinx.serialization.SerializersKt__SerializersKt.serializer(Serializers.kt:299)
	at kotlinx.serialization.SerializersKt.serializer(Unknown Source)
	at io.ktor.serialization.kotlinx.SerializerLookupKt.serializerForTypeInfo(SerializerLookup.kt:32)
	at io.ktor.serialization.kotlinx.KotlinxSerializationConverter.deserialize(KotlinxSerializationConverter.kt:66)
	at io.ktor.serialization.ContentConverterKt$deserialize$$inlined$map$1$2.emit(Emitters.kt:51)

Adding @Serializable to T fixed this in my case.

It's very frustrating and throws the user in the wrong direction. It seems to apply to all boxed types. For instance

data class Foo(val bar: Int)

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

fun main() {
    client.get("").body<Box<Foo>>()
}

Will generate a similar error statingkotlinx.serialization.SerializationException: Serializer for class 'Box' is not found.
Once again, making Foo serializable would fix this

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Ktor version: 3.1.0
KxS version: 1.8.0
Kotlin version: 2.1.0