[Serialization] Reorganize module structure

plugins/kotlinx-serialization/testData/diagnostics/SerializableEnums.kt

@@ -0,0 +1,24 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER,-UNUSED_VARIABLE
+// WITH_STDLIB
+// FILE: test.kt
+import kotlinx.serialization.*
+import kotlinx.serialization.encoding.*
+
+enum class SimpleEnum { A, B }
+
+<!EXPLICIT_SERIALIZABLE_IS_REQUIRED!>enum<!> class MarkedNameEnum { @SerialName("a") A, B}
+
+@Serializable
+enum class ExplicitlyMarkedEnum { @SerialName("a") A, B}
+
+@Serializable(EnumSerializer::class)
+enum class ExplicitlyMarkedEnumCustom { @SerialName("a") A, B}
+
+object EnumSerializer: KSerializer<ExplicitlyMarkedEnumCustom> {
+    override val descriptor = TODO()
+    override fun serialize(encoder: Encoder, value: ExplicitlyMarkedEnumCustom) = TODO()
+    override fun deserialize(decoder: Decoder): ExplicitlyMarkedEnumCustom = TODO()
+}
+
+@Serializable
+data class EnumUsage(val s: SimpleEnum, val m: MarkedNameEnum, val e: ExplicitlyMarkedEnum)