Serializing a sealead class do not set the type field

Describe the bug When serializing a single object that extends a sealed class, the type field will not be set, not allowing to deserialize it as a parent calss. To Reproduce

sealed class Parent {
  data class A(val foo: String) : Parent()
  data class B(val bar: String) : Parent()
}

val json = Json()
val a = A("hello")
val s = json.encodeToString(a)
json.decodeFromString<Parent.A>(s) // will throw

Expected behavior Field type present in the serialized object when serializing a sealed class.

Environment

• Kotlin version: 1.4.21
• Library version: 1.0.1
• Kotlin platforms: JVM
• Gradle version: 6.7.1

[sandwwraith]

The same problem here: #1194

[sandwwraith]

That’s intended behavior. Framework uses static (compile-time) types when available