Add method for getting all classifiers with given name from the scope

compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/descriptors/DeserializedMemberScope.java

@@ -160,6 +160,13 @@ public abstract class DeserializedMemberScope implements JetScope {
         return getClassDescriptor(name);
     }
 
+    @NotNull
+    @Override
+    public final Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        ClassifierDescriptor classifier = getClassifier(name);
+        return classifier != null ? Collections.singleton(classifier) : Collections.<ClassifierDescriptor>emptyList();
+    }
+
     @Nullable
     protected abstract ClassifierDescriptor getClassDescriptor(@NotNull Name name);
 

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

@@ -244,6 +244,12 @@ public class LazyImportScope implements JetScope {
         return selectFirstFromImports(name, LookupMode.ONLY_CLASSES, JetScopeSelectorUtil.CLASSIFIER_DESCRIPTOR_SCOPE_SELECTOR);
     }
 
+    @NotNull
+    @Override
+    public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        return collectFromImports(name, LookupMode.ONLY_CLASSES, JetScopeSelectorUtil.NAMED_CLASSIFIERS_SCOPE_SELECTOR);
+    }
+
     @Nullable
     @Override
     public PackageViewDescriptor getPackage(@NotNull Name name) {

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

@@ -46,7 +46,7 @@ public abstract class AbstractLazyMemberScope<D extends DeclarationDescriptor, D
     protected final DP declarationProvider;
     protected final D thisDescriptor;
 
-    private final MemoizedFunctionToNotNull<Name, List<ClassDescriptor>> classDescriptors;
+    private final MemoizedFunctionToNotNull<Name, List<ClassifierDescriptor>> classDescriptors;
 
     private final MemoizedFunctionToNotNull<Name, Set<FunctionDescriptor>> functionDescriptors;
     private final MemoizedFunctionToNotNull<Name, Set<VariableDescriptor>> propertyDescriptors;
@@ -63,9 +63,9 @@ public abstract class AbstractLazyMemberScope<D extends DeclarationDescriptor, D
         this.thisDescriptor = thisDescriptor;
 
         StorageManager storageManager = resolveSession.getStorageManager();
-        this.classDescriptors = storageManager.createMemoizedFunction(new Function1<Name, List<ClassDescriptor>>() {
+        this.classDescriptors = storageManager.createMemoizedFunction(new Function1<Name, List<ClassifierDescriptor>>() {
             @Override
-            public List<ClassDescriptor> invoke(Name name) {
+            public List<ClassifierDescriptor> invoke(Name name) {
                 return resolveClassDescriptor(name);
             }
         });
@@ -92,12 +92,12 @@ public abstract class AbstractLazyMemberScope<D extends DeclarationDescriptor, D
     }
 
     @Nullable
-    private List<ClassDescriptor> resolveClassDescriptor(@NotNull final Name name) {
+    private List<ClassifierDescriptor> resolveClassDescriptor(@NotNull final Name name) {
         Collection<JetClassOrObject> classOrObjectDeclarations = declarationProvider.getClassOrObjectDeclarations(name);
 
-        return ContainerUtil.mapNotNull(classOrObjectDeclarations, new Function<JetClassOrObject, ClassDescriptor>() {
+        return ContainerUtil.mapNotNull(classOrObjectDeclarations, new Function<JetClassOrObject, ClassifierDescriptor>() {
             @Override
-            public ClassDescriptor fun(JetClassOrObject classOrObject) {
+            public ClassifierDescriptor fun(JetClassOrObject classOrObject) {
                 return new LazyClassDescriptor(resolveSession, thisDescriptor, name, JetClassInfoUtil.createClassLikeInfo(classOrObject));
             }
         });
@@ -108,6 +108,12 @@ public abstract class AbstractLazyMemberScope<D extends DeclarationDescriptor, D
         return first(classDescriptors.invoke(name));
     }
 
+    @NotNull
+    @Override
+    public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        return classDescriptors.invoke(name);
+    }
+
     private static <T> T first(@NotNull List<T> list) {
         if (list.isEmpty()) return null;
         return list.get(0);

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

@@ -55,6 +55,12 @@ public abstract class AbstractScopeAdapter implements JetScope {
         return getWorkerScope().getClassifier(name);
     }
 
+    @NotNull
+    @Override
+    public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        return getWorkerScope().getClassifiers(name);
+    }
+
     @NotNull
     @Override
     public Collection<VariableDescriptor> getProperties(@NotNull Name name) {

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

@@ -51,6 +51,12 @@ public class ChainedScope implements JetScope {
         return getFirstMatch(scopeChain, name, CLASSIFIER_DESCRIPTOR_SCOPE_SELECTOR);
     }
 
+    @NotNull
+    @Override
+    public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        return getFromAllScopes(scopeChain, name, NAMED_CLASSIFIERS_SCOPE_SELECTOR);
+    }
+
     @Override
     public PackageViewDescriptor getPackage(@NotNull Name name) {
         return getFirstMatch(scopeChain, name, PACKAGE_SCOPE_SELECTOR);

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

@@ -66,6 +66,12 @@ public class FilteringScope implements JetScope {
         return filterDescriptor(workerScope.getClassifier(name));
     }
 
+    @NotNull
+    @Override
+    public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        return Collections2.filter(workerScope.getClassifiers(name), predicate);
+    }
+
     @NotNull
     @Override
     public Collection<VariableDescriptor> getProperties(@NotNull Name name) {

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

@@ -53,6 +53,10 @@ public interface JetScope {
     @Nullable
     ClassifierDescriptor getClassifier(@NotNull Name name);
 
+    @NotNull
+    @ReadOnly
+    Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name);
+
     @Nullable
     PackageViewDescriptor getPackage(@NotNull Name name);
 

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

@@ -34,6 +34,12 @@ public abstract class JetScopeImpl implements JetScope {
         return null;
     }
 
+    @NotNull
+    @Override
+    public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        return Collections.emptySet();
+    }
+
     @NotNull
     @Override
     public Collection<VariableDescriptor> getProperties(@NotNull Name name) {

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

@@ -112,6 +112,15 @@ public class JetScopeSelectorUtil {
                 }
             };
 
+    public static final ScopeByNameMultiSelector<ClassifierDescriptor> NAMED_CLASSIFIERS_SCOPE_SELECTOR =
+            new ScopeByNameMultiSelector<ClassifierDescriptor>() {
+                @NotNull
+                @Override
+                public Collection<ClassifierDescriptor> get(@NotNull JetScope scope, @NotNull Name name) {
+                    return scope.getClassifiers(name);
+                }
+            };
+
     public static final ScopeDescriptorSelector<DeclarationDescriptor> ALL_DESCRIPTORS_SCOPE_SELECTOR =
             new ScopeDescriptorSelector<DeclarationDescriptor>() {
                 @NotNull

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

@@ -98,6 +98,12 @@ public class SubstitutingScope implements JetScope {
         return substitute(workerScope.getClassifier(name));
     }
 
+    @NotNull
+    @Override
+    public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+        return substitute(workerScope.getClassifiers(name));
+    }
+
     @NotNull
     @Override
     public Collection<FunctionDescriptor> getFunctions(@NotNull Name name) {

core/descriptors/src/org/jetbrains/jet/lang/types/ErrorUtils.java

@@ -85,6 +85,12 @@ public class ErrorUtils {
             return ERROR_CLASS;
         }
 
+        @NotNull
+        @Override
+        public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+            return ERROR_CLASSIFIER_GROUP;
+        }
+
         @NotNull
         @Override
         public Set<VariableDescriptor> getProperties(@NotNull Name name) {
@@ -161,6 +167,12 @@ public class ErrorUtils {
             throw new IllegalStateException();
         }
 
+        @NotNull
+        @Override
+        public Collection<ClassifierDescriptor> getClassifiers(@NotNull Name name) {
+            throw new IllegalStateException();
+        }
+
         @Nullable
         @Override
         public PackageViewDescriptor getPackage(@NotNull Name name) {
@@ -254,6 +266,7 @@ public class ErrorUtils {
             ERROR_PROPERTY_TYPE,
             CallableMemberDescriptor.Kind.DECLARATION);
     private static final Set<VariableDescriptor> ERROR_PROPERTY_GROUP = Collections.singleton(ERROR_PROPERTY);
+    private static final Set<ClassifierDescriptor> ERROR_CLASSIFIER_GROUP = Collections.<ClassifierDescriptor>singleton(ERROR_CLASS);
 
     @NotNull
     private static SimpleFunctionDescriptor createErrorFunction(@NotNull ErrorScope ownerScope) {