Serialization with sealed classes fails in Kotlin serialization

I'm having trouble with kotlin-serialization in the following use case:

@Serializable
sealed class NetworkAnswer {
    @SerialName("answerId")
    abstract val id: Int
}

@Serializable
data class NetworkYesNoAnswer(
    override val id: Int,

    @SerialName("isPositive")
    val isPositive: Boolean
) : NetworkAnswer()

When I serialize this:

val json = Json { ignoreUnknownKeys = true; explicitNulls = false }
val result: NetworkYesNoAnswer = json.decodeFromString(NetworkYesNoAnswer.serializer(), """
            { 
            "answerId": 1, 
            "isPositive": true 
            }
  """.trimIndent()
)

I get the following error

Caused by: kotlinx.serialization.MissingFieldException: Fields [id] are required for type with serial name 'NetworkYesNoAnswer', but they were missing

The only way the serialization works is if I use the same name for both the member and "SerialName", like so:

@Serializable
sealed class NetworkAnswer {
    @SerialName("answerId")
    abstract val answerId: Int
}

@Serializable
data class NetworkYesNoAnswer(
    override val answerId: Int,

    @SerialName("isPositive")
    val isPositive: Boolean
) : NetworkAnswer()

This kinda defeats the purpose of "SerialName", is there a way to solve that without using the same name?

Declaring a @SerialName on a base class has no effect on member declarations overridden by child classes.

Instead, you can declare @SerialName on the child class instead. There is no need to change the actual name of the field.

@Serializable
data class NetworkYesNoAnswer(
    @SerialName("answerId")
    override val id: Int,

    @SerialName("isPositive")
    val isPositive: Boolean
) : NetworkAnswer()

Declaring the @SerialName on the base class and applying it to all children seems NOT to be supported as of now, but is desired by other members of the community as well, e.g. here on GitHub.

OT: Most likely you could use a sealed interface, which was first introduced in Kotlin v1.5.0, instead of a sealed class.