[Serialization] Reorganize module structure

plugins/kotlinx-serialization/testData/firMembers/enums.kt

@@ -0,0 +1,45 @@
+
+// WITH_STDLIB
+
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.internal.*
+
+enum class Plain {
+    A, B
+}
+
+@Serializable enum class WithNames {
+    @SerialName("A") ENTRY1,
+    @SerialName("B") ENTRY2
+}
+
+@Serializable
+class Holder(val p: Plain, val w: WithNames)
+
+@OptIn(InternalSerializationApi::class)
+fun testSerializers(): String {
+    val cs = (Holder.serializer() as GeneratedSerializer<*>).childSerializers()
+    val str1 = cs[0].toString()
+    if (!str1.contains("kotlinx.serialization.internal.EnumSerializer")) return str1
+
+    /**
+     * Serialization 1.4.1+ have runtime factories to create EnumSerializer instead of synthetic $serializer, saving bytecode
+     * and bringing consistency. After updating the version, uncomment this block.
+     */
+//    val str2 = cs[1].toString()
+//    if (!str2.contains("kotlinx.serialization.internal.EnumSerializer")) return str2
+    return "OK"
+}
+
+fun testSerialization(previous: String): String {
+    if (previous != "OK") return previous
+    val h = Holder(Plain.B, WithNames.ENTRY1)
+    val s = Json.encodeToString(Holder.serializer(), h)
+    if (s != """{"p":"B","w":"A"}""") return s
+    return "OK"
+}
+
+fun box(): String {
+    return testSerialization(testSerializers())
+}