asserts in JetScopeImpl, add enum entry to proper scope

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

@@ -260,4 +260,15 @@ public class DescriptorUtils {
         }
         return expectedType != null ? expectedType : TypeUtils.NO_EXPECTED_TYPE;
     }
+
+    public static boolean isObject(@NotNull ClassifierDescriptor classifier) {
+        if (classifier instanceof ClassDescriptor) {
+            ClassDescriptor clazz = (ClassDescriptor) classifier;
+            return clazz.getKind() == ClassKind.OBJECT || clazz.getKind() == ClassKind.ENUM_ENTRY;
+        } else if (classifier instanceof TypeParameterDescriptor) {
+            return false;
+        } else {
+            throw new IllegalStateException("unknown classifier: " + classifier);
+        }
+    }
 }

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

@@ -164,7 +164,7 @@ public class TypeHierarchyResolver {
                             (Map) context.getClasses(),
                             mutableClassDescriptor
                     );
-                    classObjectDescriptor.addClassifierDescriptor(mutableClassDescriptor);
+                    classObjectDescriptor.addObjectDescriptor(mutableClassDescriptor);
                 }
 
                 private MutableClassDescriptor createClassDescriptorForObject(@NotNull JetClassOrObject declaration, @NotNull NamespaceLike owner, JetScope scope, ClassKind classKind) {

compiler/frontend/src/org/jetbrains/jet/lang/resolve/scopes/WritableScopeImpl.java

@@ -23,6 +23,7 @@ import com.google.common.collect.Sets;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.*;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.ReceiverDescriptor;
 import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
 import org.jetbrains.jet.util.CommonSuppliers;
@@ -308,12 +309,20 @@ public class WritableScopeImpl extends WritableScopeWithImports {
     public void addClassifierDescriptor(@NotNull ClassifierDescriptor classDescriptor) {
         checkMayWrite();
 
+        if (DescriptorUtils.isObject(classDescriptor)) {
+            throw new IllegalStateException("must not be object: " + classDescriptor);
+        }
+
         addClassifierAlias(classDescriptor.getName(), classDescriptor);
     }
 
     @Override
     public void addObjectDescriptor(@NotNull ClassDescriptor objectDescriptor) {
         checkMayWrite();
+
+        if (!DescriptorUtils.isObject(objectDescriptor)) {
+            throw new IllegalStateException("must be object: " + objectDescriptor);
+        }
         
         getObjectDescriptorsMap().put(objectDescriptor.getName(), objectDescriptor);
     }