Move utility method to DescriptorUtils and make it more general

core/descriptors/src/org/jetbrains/jet/lang/resolve/DescriptorUtils.java

@@ -238,6 +238,14 @@ public class DescriptorUtils {
         return isKindOf(descriptor, ClassKind.ENUM_ENTRY);
     }
 
+    public static boolean isObject(@NotNull DeclarationDescriptor classifier) {
+        if (classifier instanceof ClassDescriptor) {
+            ClassDescriptor clazz = (ClassDescriptor) classifier;
+            return clazz.getKind().isObject();
+        }
+        return false;
+    }
+
     public static boolean isEnumClass(@NotNull DeclarationDescriptor descriptor) {
         return isKindOf(descriptor, ClassKind.ENUM_CLASS);
     }
@@ -475,4 +483,4 @@ public class DescriptorUtils {
         assert classObject != null : "Enum class should have a class object: " + enumClass;
         return classObject.getDefaultType().getMemberScope();
     }
-}
+}

core/descriptors/src/org/jetbrains/jet/lang/resolve/scopes/WritableScopeImpl.java

@@ -21,6 +21,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.TestOnly;
 import org.jetbrains.jet.lang.descriptors.*;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
 import org.jetbrains.jet.lang.resolve.name.LabelName;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
@@ -309,7 +310,7 @@ public class WritableScopeImpl extends WritableScopeWithImports {
     public void addClassifierDescriptor(@NotNull ClassifierDescriptor classDescriptor) {
         checkMayWrite();
 
-        if (isObject(classDescriptor)) {
+        if (DescriptorUtils.isObject(classDescriptor)) {
             throw new IllegalStateException("must not be object: " + classDescriptor);
         }
 
@@ -497,19 +498,6 @@ public class WritableScopeImpl extends WritableScopeWithImports {
         return declaredDescriptorsAccessibleBySimpleName.values();
     }
 
-    private static boolean isObject(@NotNull ClassifierDescriptor classifier) {
-        if (classifier instanceof ClassDescriptor) {
-            ClassDescriptor clazz = (ClassDescriptor) classifier;
-            return clazz.getKind().isObject();
-        }
-        else if (classifier instanceof TypeParameterDescriptor) {
-            return false;
-        }
-        else {
-            throw new IllegalStateException("unknown classifier: " + classifier);
-        }
-    }
-
     @TestOnly
     @Override
     protected void printAdditionalScopeStructure(@NotNull Printer p) {