Report a proper error on class object in enum entry or object

CLASS_OBJECT_NOT_ALLOWED instead of MANY_CLASS_OBJECTS

compiler/frontend/src/org/jetbrains/jet/lang/resolve/TypeHierarchyResolver.java

@@ -45,6 +45,8 @@ import java.util.*;
 import static org.jetbrains.jet.lang.diagnostics.Errors.*;
 import static org.jetbrains.jet.lang.resolve.BindingContext.FQNAME_TO_CLASS_DESCRIPTOR;
 import static org.jetbrains.jet.lang.resolve.BindingContext.TYPE;
+import static org.jetbrains.jet.lang.resolve.DescriptorUtils.isEnumEntry;
+import static org.jetbrains.jet.lang.resolve.DescriptorUtils.isObject;
 import static org.jetbrains.jet.lang.resolve.ModifiersChecker.getDefaultClassVisibility;
 import static org.jetbrains.jet.lang.resolve.ModifiersChecker.resolveVisibilityFromModifiers;
 import static org.jetbrains.jet.lang.resolve.name.SpecialNames.getClassObjectName;
@@ -508,11 +510,16 @@ public class TypeHierarchyResolver {
             JetObjectDeclaration objectDeclaration = classObject.getObjectDeclaration();
             if (objectDeclaration == null) return;
 
-            MutableClassDescriptor classObjectDescriptor =
-                    createClassDescriptorForSingleton(objectDeclaration, getClassObjectName(owner.getOwnerForChildren().getName()),
-                                                      ClassKind.CLASS_OBJECT);
+            DeclarationDescriptor container = owner.getOwnerForChildren();
+
+            MutableClassDescriptor classObjectDescriptor =
+                    createClassDescriptorForSingleton(objectDeclaration, getClassObjectName(container.getName()), ClassKind.CLASS_OBJECT);
+
+            NamespaceLikeBuilder.ClassObjectStatus status =
+                    isEnumEntry(container) || isObject(container) ?
+                    NamespaceLikeBuilder.ClassObjectStatus.NOT_ALLOWED :
+                    owner.setClassObjectDescriptor(classObjectDescriptor);
 
-            NamespaceLikeBuilder.ClassObjectStatus status = owner.setClassObjectDescriptor(classObjectDescriptor);
             switch (status) {
                 case DUPLICATE:
                     trace.report(MANY_CLASS_OBJECTS.on(classObject));

compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.kt

@@ -0,0 +1,11 @@
+enum class E {
+    FIRST
+
+    SECOND {
+        <!CLASS_OBJECT_NOT_ALLOWED!>class object {
+            fun foo() = 42
+        }<!>
+    }
+}
+
+fun f() = E.SECOND.<!UNRESOLVED_REFERENCE!>foo<!>()

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -2542,6 +2542,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/enum/entryShouldBeOfEnumType.kt");
             }
             
+            @TestMetadata("enumEntryCannotHaveClassObject.kt")
+            public void testEnumEntryCannotHaveClassObject() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.kt");
+            }
+            
             @TestMetadata("enumInheritance.kt")
             public void testEnumInheritance() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/enum/enumInheritance.kt");