Class objects also can have delegated members

compiler/frontend/src/org/jetbrains/jet/lang/resolve/lazy/descriptors/LazyClassMemberScope.java

@@ -261,10 +261,12 @@ public class LazyClassMemberScope extends AbstractLazyMemberScope<LazyClassDescr
             @NotNull final MemberExtractor<T> extractor,
             @NotNull Collection<? extends CallableDescriptor> existingDescriptors
     ) {
-        //class objects do not have delegated members
-        if (thisDescriptor.getKind() == ClassKind.CLASS_OBJECT) {
+        JetClassOrObject classOrObject = declarationProvider.getOwnerInfo().getCorrespondingClassOrObject();
+        if (classOrObject == null) {
+            // Enum class objects do not have delegated members
             return Collections.emptySet();
         }
+
         DelegationResolver.TypeResolver lazyTypeResolver = new DelegationResolver.TypeResolver() {
             @Nullable
             @Override
@@ -283,8 +285,6 @@ public class LazyClassMemberScope extends AbstractLazyMemberScope<LazyClassDescr
                 return extractor.extract(type, name);
             }
         };
-        JetClassOrObject classOrObject = declarationProvider.getOwnerInfo().getCorrespondingClassOrObject();
-        assert classOrObject != null : "Should not be null for non class object class.";
         return generateDelegatedMembers(classOrObject, thisDescriptor, existingDescriptors, resolveSession.getTrace(), lazyMemberExtractor,
                                         lazyTypeResolver);
     }

compiler/testData/loadKotlin/classObject/Delegation.kt

@@ -0,0 +1,11 @@
+package test
+
+trait T {
+    fun foo(): Int
+}
+
+class A : T {
+    override fun foo() = 42
+
+    class object : T by A()
+}

compiler/testData/loadKotlin/classObject/Delegation.txt

@@ -0,0 +1,15 @@
+package test
+
+internal final class A : test.T {
+    /*primary*/ public constructor A()
+    internal open override /*1*/ fun foo(): jet.Int
+    
+    internal class object <class-object-for-A> : test.T {
+        /*primary*/ private constructor <class-object-for-A>()
+        internal open override /*1*/ /*delegation*/ fun foo(): jet.Int
+    }
+}
+
+internal trait T {
+    internal abstract fun foo(): jet.Int
+}

compiler/tests/org/jetbrains/jet/descriptors/serialization/DescriptorSerializationTestGenerated.java

@@ -294,6 +294,11 @@ public class DescriptorSerializationTestGenerated extends AbstractDescriptorSeri
             doTest("compiler/testData/loadKotlin/classObject/ClassObjectPropertyInClass.kt");
         }
         
+        @TestMetadata("Delegation.kt")
+        public void testDelegation() throws Exception {
+            doTest("compiler/testData/loadKotlin/classObject/Delegation.kt");
+        }
+        
         @TestMetadata("InnerClassInClassObject.kt")
         public void testInnerClassInClassObject() throws Exception {
             doTest("compiler/testData/loadKotlin/classObject/InnerClassInClassObject.kt");

compiler/tests/org/jetbrains/jet/jvm/compiler/LoadCompiledKotlinTestGenerated.java

@@ -568,6 +568,11 @@ public class LoadCompiledKotlinTestGenerated extends AbstractLoadCompiledKotlinT
             doTestWithAccessors("compiler/testData/loadKotlin/classObject/ClassObjectPropertyInClass.kt");
         }
         
+        @TestMetadata("Delegation.kt")
+        public void testDelegation() throws Exception {
+            doTestWithAccessors("compiler/testData/loadKotlin/classObject/Delegation.kt");
+        }
+        
         @TestMetadata("InnerClassInClassObject.kt")
         public void testInnerClassInClassObject() throws Exception {
             doTestWithAccessors("compiler/testData/loadKotlin/classObject/InnerClassInClassObject.kt");

compiler/tests/org/jetbrains/jet/lang/resolve/lazy/LazyResolveNamespaceComparingTestGenerated.java

@@ -570,6 +570,11 @@ public class LazyResolveNamespaceComparingTestGenerated extends AbstractLazyReso
                 doTestCheckingPrimaryConstructorsAndAccessors("compiler/testData/loadKotlin/classObject/ClassObjectPropertyInClass.kt");
             }
             
+            @TestMetadata("Delegation.kt")
+            public void testDelegation() throws Exception {
+                doTestCheckingPrimaryConstructorsAndAccessors("compiler/testData/loadKotlin/classObject/Delegation.kt");
+            }
+            
             @TestMetadata("InnerClassInClassObject.kt")
             public void testInnerClassInClassObject() throws Exception {
                 doTestCheckingPrimaryConstructorsAndAccessors("compiler/testData/loadKotlin/classObject/InnerClassInClassObject.kt");