Add ClassDescriptor#isDefaultObject()

with dummy implementations for now

compiler/frontend/src/org/jetbrains/kotlin/descriptors/impl/MutableClassDescriptor.java

@@ -143,6 +143,11 @@ public class MutableClassDescriptor extends ClassDescriptorBase implements Class
         return isInner;
     }
 
+    @Override
+    public boolean isDefaultObject() {
+        return getKind() == ClassKind.CLASS_OBJECT;
+    }
+
     @NotNull
     @Override
     public TypeConstructor getTypeConstructor() {

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyClassDescriptor.java

@@ -439,6 +439,11 @@ public class LazyClassDescriptor extends ClassDescriptorBase implements ClassDes
         return isInner;
     }
 
+    @Override
+    public boolean isDefaultObject() {
+        return getKind() == ClassKind.CLASS_OBJECT;
+    }
+
     @NotNull
     @Override
     public Annotations getAnnotations() {

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/lazy/descriptors/LazyJavaClassDescriptor.kt

@@ -100,6 +100,8 @@ class LazyJavaClassDescriptor(
 
     override fun getFunctionTypeForSamInterface(): JetType? = functionTypeForSamInterface()
 
+    override fun isDefaultObject() = false
+
     override fun toString() = "lazy java class $fqName"
 
     private inner class LazyJavaClassTypeConstructor : AbstractClassTypeConstructor() {

core/descriptors/src/org/jetbrains/kotlin/descriptors/ClassDescriptor.java

@@ -82,6 +82,8 @@ public interface ClassDescriptor extends ClassifierDescriptor, MemberDescriptor,
      */
     boolean isInner();
 
+    boolean isDefaultObject();
+
     @NotNull
     ReceiverParameterDescriptor getThisAsReceiverParameter();
 

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

@@ -111,6 +111,11 @@ public class ClassDescriptorImpl extends ClassDescriptorBase {
         return ClassKind.CLASS;
     }
 
+    @Override
+    public boolean isDefaultObject() {
+        return false;
+    }
+
     @Override
     public ConstructorDescriptor getUnsubstitutedPrimaryConstructor() {
         return primaryConstructor;

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

@@ -142,6 +142,11 @@ public class EnumEntrySyntheticClassDescriptor extends ClassDescriptorBase {
         return false;
     }
 
+    @Override
+    public boolean isDefaultObject() {
+        return false;
+    }
+
     @Nullable
     @Override
     public ConstructorDescriptor getUnsubstitutedPrimaryConstructor() {

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

@@ -196,6 +196,11 @@ public class LazySubstitutingClassDescriptor implements ClassDescriptor {
         return original.isInner();
     }
 
+    @Override
+    public boolean isDefaultObject() {
+        return original.isDefaultObject();
+    }
+
     @Override
     public <R, D> R accept(DeclarationDescriptorVisitor<R, D> visitor, D data) {
         return visitor.visitClassDescriptor(this, data);

core/serialization/src/org/jetbrains/kotlin/serialization/deserialization/descriptors/DeserializedClassDescriptor.kt

@@ -88,6 +88,8 @@ public class DeserializedClassDescriptor(
 
     override fun getStaticScope() = staticScope
 
+    override fun isDefaultObject(): Boolean = getKind() == ClassKind.CLASS_OBJECT
+
     private fun computePrimaryConstructor(): ConstructorDescriptor? {
         if (!classProto.hasPrimaryConstructor()) return null