Fix ClassKind for Serializable and change ClassKind to INTERFACE for error classes.

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/kotlin/BuiltInClassesAreSerializableOnJvm.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.load.kotlin
 
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.SourceElement
@@ -53,7 +54,7 @@ class BuiltInClassesAreSerializableOnJvm(
         })
 
         val mockSerializableClass = ClassDescriptorImpl(
-                mockJavaIoPackageFragment, Name.identifier("Serializable"), Modality.ABSTRACT, superTypes, SourceElement.NO_SOURCE
+                mockJavaIoPackageFragment, Name.identifier("Serializable"), Modality.ABSTRACT, ClassKind.INTERFACE, superTypes, SourceElement.NO_SOURCE
         )
 
         mockSerializableClass.initialize(MemberScope.Empty, emptySet(), null)

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/ClassDescriptorImpl.java

@@ -35,6 +35,7 @@ import java.util.Set;
 
 public class ClassDescriptorImpl extends ClassDescriptorBase {
     private final Modality modality;
+    private final ClassKind kind;
     private final TypeConstructor typeConstructor;
     private final MemberScope staticScope = new StaticScopeForKotlinClass(this);
 
@@ -46,11 +47,13 @@ public class ClassDescriptorImpl extends ClassDescriptorBase {
             @NotNull DeclarationDescriptor containingDeclaration,
             @NotNull Name name,
             @NotNull Modality modality,
+            @NotNull ClassKind kind,
             @NotNull Collection<KotlinType> supertypes,
             @NotNull SourceElement source
     ) {
         super(LockBasedStorageManager.NO_LOCKS, containingDeclaration, name, source);
         this.modality = modality;
+        this.kind = kind;
 
         this.typeConstructor = TypeConstructorImpl.createForClass(this, Annotations.Companion.getEMPTY(), false, getName().asString(),
                                                        Collections.<TypeParameterDescriptor>emptyList(), supertypes);
@@ -109,7 +112,7 @@ public class ClassDescriptorImpl extends ClassDescriptorBase {
     @NotNull
     @Override
     public ClassKind getKind() {
-        return ClassKind.CLASS;
+        return kind;
     }
 
     @Override

core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java

@@ -255,7 +255,7 @@ public class ErrorUtils {
     private static class ErrorClassDescriptor extends ClassDescriptorImpl {
         public ErrorClassDescriptor(@Nullable String name) {
             super(getErrorModule(), Name.special(name == null ? "<ERROR CLASS>" : "<ERROR CLASS: " + name + ">"),
-                  Modality.OPEN, Collections.<KotlinType>emptyList(), SourceElement.NO_SOURCE);
+                  Modality.OPEN, ClassKind.CLASS, Collections.<KotlinType>emptyList(), SourceElement.NO_SOURCE);
 
             ConstructorDescriptorImpl errorConstructor = ConstructorDescriptorImpl.create(this, Annotations.Companion.getEMPTY(), true, SourceElement.NO_SOURCE);
             errorConstructor.initialize(Collections.<ValueParameterDescriptor>emptyList(),