diff --git a/platform/lang-api/src/com/intellij/psi/impl/include/FileIncludeManager.java b/platform/lang-api/src/com/intellij/psi/impl/include/FileIncludeManager.java
index 7d56a7e75cb2..3d3e7a04fd1c 100644
--- a/platform/lang-api/src/com/intellij/psi/impl/include/FileIncludeManager.java
+++ b/platform/lang-api/src/com/intellij/psi/impl/include/FileIncludeManager.java
@@ -23,6 +23,7 @@ import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiFile;
 import com.intellij.psi.PsiFileSystemItem;
 import com.intellij.util.Processor;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
@@ -34,9 +35,9 @@ public abstract class FileIncludeManager {
     return ServiceManager.getService(project, FileIncludeManager.class);
   }
 
-  public abstract VirtualFile[] getIncludedFiles(VirtualFile file, boolean compileTimeOnly);
+  public abstract VirtualFile[] getIncludedFiles(@NotNull VirtualFile file, boolean compileTimeOnly);
 
-  public abstract VirtualFile[] getIncludingFiles(VirtualFile file, boolean compileTimeOnly);
+  public abstract VirtualFile[] getIncludingFiles(@NotNull VirtualFile file, boolean compileTimeOnly);
 
   public abstract void processIncludingFiles(PsiFile context, Processor<Pair<VirtualFile, FileIncludeInfo>> processor);
 
diff --git a/platform/lang-impl/src/com/intellij/psi/impl/include/FileIncludeManagerImpl.java b/platform/lang-impl/src/com/intellij/psi/impl/include/FileIncludeManagerImpl.java
index 01340d441c00..c141d5b270a4 100644
--- a/platform/lang-impl/src/com/intellij/psi/impl/include/FileIncludeManagerImpl.java
+++ b/platform/lang-impl/src/com/intellij/psi/impl/include/FileIncludeManagerImpl.java
@@ -21,10 +21,7 @@ import com.intellij.openapi.fileTypes.StdFileTypes;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.Pair;
-import com.intellij.openapi.vfs.VfsUtil;
-import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.openapi.vfs.VirtualFileManager;
-import com.intellij.openapi.vfs.VirtualFileWithId;
+import com.intellij.openapi.vfs.*;
 import com.intellij.psi.PsiFile;
 import com.intellij.psi.PsiFileFactory;
 import com.intellij.psi.PsiFileSystemItem;
@@ -38,6 +35,7 @@ import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.FactoryMap;
 import com.intellij.util.containers.HashMap;
 import com.intellij.util.containers.MultiMap;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
@@ -136,7 +134,7 @@ public class FileIncludeManagerImpl extends FileIncludeManager {
   }
 
   @Override
-  public VirtualFile[] getIncludedFiles(VirtualFile file, boolean compileTimeOnly) {
+  public VirtualFile[] getIncludedFiles(@NotNull VirtualFile file, boolean compileTimeOnly) {
     if (file instanceof VirtualFileWithId) {
       return myIncludedHolder.getAllFiles(file, compileTimeOnly);
     }
@@ -146,7 +144,7 @@ public class FileIncludeManagerImpl extends FileIncludeManager {
   }
 
   @Override
-  public VirtualFile[] getIncludingFiles(VirtualFile file, boolean compileTimeOnly) {
+  public VirtualFile[] getIncludingFiles(@NotNull VirtualFile file, boolean compileTimeOnly) {
     return myIncludingHolder.getAllFiles(file, compileTimeOnly);
   }
 
@@ -204,13 +202,13 @@ public class FileIncludeManagerImpl extends FileIncludeManager {
       RUNTIME_KEY = Key.create(runtimeKey);
     }
 
-    public VirtualFile[] getAllFiles(VirtualFile file, boolean compileTimeOnly) {
+    private VirtualFile[] getAllFiles(@NotNull VirtualFile file, boolean compileTimeOnly) {
       Set<VirtualFile> result = new HashSet<VirtualFile>();
       getFilesRecursively(file, compileTimeOnly, result);
-      return VfsUtil.toVirtualFileArray(result);
+      return VfsUtilCore.toVirtualFileArray(result);
     }
 
-    private void getFilesRecursively(VirtualFile file, boolean compileTimeOnly, Set<VirtualFile> result) {
+    private void getFilesRecursively(@NotNull VirtualFile file, boolean compileTimeOnly, Set<VirtualFile> result) {
       if (result.contains(file)) return;
       PsiFile psiFile = myPsiManager.findFile(file);
       if (psiFile == null) return;
diff --git a/xml/relaxng/src/org/intellij/plugins/relaxNG/model/resolve/RelaxIncludeIndex.java b/xml/relaxng/src/org/intellij/plugins/relaxNG/model/resolve/RelaxIncludeIndex.java
index 0d8c9c5de2cc..ab9beda8cc01 100644
--- a/xml/relaxng/src/org/intellij/plugins/relaxNG/model/resolve/RelaxIncludeIndex.java
+++ b/xml/relaxng/src/org/intellij/plugins/relaxNG/model/resolve/RelaxIncludeIndex.java
@@ -23,20 +23,23 @@ import org.jetbrains.annotations.NotNull;
 */
 public class RelaxIncludeIndex {
   public static boolean processForwardDependencies(XmlFile file, final PsiElementProcessor<XmlFile> processor) {
+    VirtualFile virtualFile = file.getVirtualFile();
+    if (virtualFile == null) {
+      return processor.execute(file);
+    }
     final Project project = file.getProject();
-    final VirtualFile[] files = FileIncludeManager.getManager(project).getIncludedFiles(file.getVirtualFile(), true);
+    final VirtualFile[] files = FileIncludeManager.getManager(project).getIncludedFiles(virtualFile, true);
 
     return processRelatedFiles(file, files, processor);
   }
 
   public static boolean processBackwardDependencies(@NotNull XmlFile file, PsiElementProcessor<XmlFile> processor) {
-    return processBackwardDependencies((PsiFile)file, processor);
-  }
-
-
-  private static boolean processBackwardDependencies(@NotNull PsiFile file, PsiElementProcessor<XmlFile> processor) {
+    VirtualFile virtualFile = file.getVirtualFile();
+    if (virtualFile == null) {
+      return processor.execute(file);
+    }
     final Project project = file.getProject();
-    final VirtualFile[] files = FileIncludeManager.getManager(project).getIncludingFiles(file.getVirtualFile(), true);
+    final VirtualFile[] files = FileIncludeManager.getManager(project).getIncludingFiles(virtualFile, true);
 
     return processRelatedFiles(file, files, processor);
   }
@@ -51,25 +54,28 @@ public class RelaxIncludeIndex {
     });
 
     for (final PsiFile psiFile : psiFiles) {
-      final FileType type = file.getFileType();
-      if (type == XmlFileType.INSTANCE && isRngFile(psiFile)) {
-        if (!processor.execute((XmlFile)psiFile)) {
-          return false;
-        }
-      } else if (type == RncFileType.getInstance()) {
-        if (!processor.execute((XmlFile)psiFile)) {
-          return false;
-        }
+      if (!processFile(psiFile, processor)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  private static boolean processFile(PsiFile psiFile, PsiElementProcessor<XmlFile> processor) {
+    final FileType type = psiFile.getFileType();
+    if (type == XmlFileType.INSTANCE && isRngFile(psiFile)) {
+      if (!processor.execute((XmlFile)psiFile)) {
+        return false;
+      }
+    } else if (type == RncFileType.getInstance()) {
+      if (!processor.execute((XmlFile)psiFile)) {
+        return false;
       }
     }
     return true;
   }
 
   static boolean isRngFile(PsiFile psiFile) {
-    try {
-      return DomManager.getDomManager(psiFile.getProject()).getFileElement((XmlFile)psiFile, RngGrammar.class) != null;
-    } catch (ClassCastException e) {
-      return false; // fileType == XML && !instanceof XmlFile
-    }
+     return psiFile instanceof XmlFile && DomManager.getDomManager(psiFile.getProject()).getFileElement((XmlFile)psiFile, RngGrammar.class) != null;
   }
 }