Review all changes since commit 41c0bb1, improving some code and comm…

…ents and reverting some unnecessary changes

core/commonMain/src/kotlinx/serialization/Annotations.kt

@@ -153,7 +153,7 @@ public annotation class Serializer(
 public annotation class SerialName(val value: String)
 
 /**
- * Requires all subclasses to use [SerialPolymorphicNumber].
+ * Requires all subclasses marked with this annotation to use [SerialPolymorphicNumber].
  */
 @SerialInfo
 @Target(AnnotationTarget.CLASS)

core/commonMain/src/kotlinx/serialization/SealedSerializer.kt

@@ -127,7 +127,6 @@ public class SealedClassSerializer<T : Any>(
         // Plugin should produce identical serializers, although they are not always strictly equal (e.g. new ObjectSerializer
         // may be created every time)
         class2Serializer = subclasses.zip(subclassSerializers).toMap()
-
         serialName2Serializer = class2Serializer.entries.groupingBy { it.value.descriptor.serialName }
             .aggregate<Map.Entry<KClass<out T>, KSerializer<out T>>, String, Map.Entry<KClass<*>, KSerializer<out T>>>
             { key, accumulator, element, _ ->

core/commonMain/src/kotlinx/serialization/internal/AbstractPolymorphicSerializer.kt

@@ -143,11 +143,11 @@ internal fun throwSubtypeNotRegistered(serialPolymorphicNumber: Int?, baseClass:
     throw SerializationException(
         (
             if (serialPolymorphicNumber == null)
-                "Class discriminator serial polymorphic number was missing and no default serializers were registered $scope."
+                "Class discriminator (serial polymorphic number) was missing and no default serializers were registered $scope."
             else
-                "Serializer for subclass serial polymorphic number '$serialPolymorphicNumber' is not found $scope.\n" +
+                "Serializer for subclass serial polymorphic number '$serialPolymorphicNumber' is not found in $scope.\n" +
                     "Check if class with serial polymorphic number '$serialPolymorphicNumber' exists and serializer is registered in a corresponding SerializersModule.\n" +
-                    "To be registered automatically, class annotated with '@SerialPolymorphicNumber($serialPolymorphicNumber)' has to be '@Serializable', and the base class '${baseClass.simpleName}' has to be sealed and '@Serializable'.\n"
+                    "To be registered automatically, class annotated with '@SerialPolymorphicNumber($serialPolymorphicNumber)' has to be '@Serializable', and the base class '${baseClass.simpleName}' marked with `@UseSerialPolymorphicNumbers` has to be sealed and '@Serializable'.\n"
             ) +
             "\nRemove the `@UseSerialPolymorphicNumbers` annotation from the base class `${baseClass.simpleName}` if you want to switch back to polymorphic serialization using the serial name strings."
     )

core/commonMain/src/kotlinx/serialization/modules/SerializersModuleBuilders.kt

@@ -188,7 +188,7 @@ public class SerializersModuleBuilder @PublishedApi internal constructor() : Ser
     internal fun <Base : Any> registerDefaultPolymorphicDeserializer(
         baseClass: KClass<Base>,
         defaultDeserializerProvider: (className: String?) -> DeserializationStrategy<Base>?,
-        //defaultDeserializerProvider: PolymorphicDeserializerProvider<Base>,
+        //defaultDeserializerProvider: PolymorphicDeserializerProvider<Base>, // this causes the build to fail on JS, but only when there is no trailing comment such as this one, which is strange
         allowOverwrite: Boolean
     ) {
         val previous = polyBase2DefaultDeserializerProvider[baseClass]
@@ -202,7 +202,7 @@ public class SerializersModuleBuilder @PublishedApi internal constructor() : Ser
     internal fun <Base : Any> registerDefaultPolymorphicDeserializerForNumber(
         baseClass: KClass<Base>,
         defaultDeserializerProvider: (polymorphicSerialNumber: Int?) -> DeserializationStrategy<Base>?,
-        //defaultDeserializerProvider: PolymorphicDeserializerProviderForNumber<Base>,
+        //defaultDeserializerProvider: PolymorphicDeserializerProviderForNumber<Base>, // this causes the build to fail on JS, but only when there is no trailing comment such as this one, which is strange
         allowOverwrite: Boolean
     ) {
         val previous = polyBase2DefaultDeserializerProviderForNumber[baseClass]