JS: serialize type of local anonymous class as its denotable supertype. See KT-14888

compiler/serialization/src/org/jetbrains/kotlin/serialization/SerializerExtensionBase.kt

@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.resolve.constants.NullValue
 import org.jetbrains.kotlin.types.KotlinType
 
 open class KotlinSerializerExtensionBase(private val protocol: SerializerExtensionProtocol) : SerializerExtension() {
-    override final val stringTable = StringTableImpl()
+    override val stringTable = StringTableImpl()
 
     override fun serializeClass(descriptor: ClassDescriptor, proto: ProtoBuf.Class.Builder) {
         for (annotation in descriptor.annotations) {

compiler/serialization/src/org/jetbrains/kotlin/serialization/StringTableImpl.kt

@@ -26,7 +26,7 @@ import org.jetbrains.kotlin.types.ErrorUtils
 import org.jetbrains.kotlin.utils.Interner
 import java.io.OutputStream
 
-class StringTableImpl : StringTable {
+open class StringTableImpl : StringTable {
     private class FqNameProto(val fqName: QualifiedName.Builder) {
         override fun hashCode(): Int {
             var result = 13
@@ -72,7 +72,7 @@ class StringTableImpl : StringTable {
             is ClassDescriptor -> {
                 builder.parentQualifiedName = getFqNameIndex(containingDeclaration)
             }
-            else -> throw IllegalStateException("Cannot get FQ name of local class: " + descriptor)
+            else -> return getFqNameIndexOfLocalAnonymousClass(descriptor)
         }
 
         builder.shortName = getStringIndex(descriptor.name.asString())
@@ -80,6 +80,10 @@ class StringTableImpl : StringTable {
         return qualifiedNames.intern(FqNameProto(builder))
     }
 
+    open fun getFqNameIndexOfLocalAnonymousClass(descriptor: ClassifierDescriptorWithTypeParameters): Int {
+        throw IllegalStateException("Cannot get FQ name of local class: " + descriptor)
+    }
+
     fun getPackageFqNameIndex(fqName: FqName): Int {
         var result = -1
         for (segment in fqName.pathSegments()) {