diff --git a/platform/indexing-impl/src/com/intellij/psi/impl/cache/impl/id/IdIndex.java b/platform/indexing-impl/src/com/intellij/psi/impl/cache/impl/id/IdIndex.java
index 5022ede110fa..43fc91fc1c5c 100644
--- a/platform/indexing-impl/src/com/intellij/psi/impl/cache/impl/id/IdIndex.java
+++ b/platform/indexing-impl/src/com/intellij/psi/impl/cache/impl/id/IdIndex.java
@@ -29,7 +29,7 @@ import java.util.Map;
  * Consider usage of {@link com.intellij.psi.search.PsiSearchHelper} or {@link com.intellij.psi.impl.cache.CacheManager} instead direct index access.
  */
 @ApiStatus.Internal
-public class IdIndex extends FileBasedIndexExtension<IdIndexEntry, Integer> implements DocumentChangeDependentIndex {
+public class IdIndex extends FileBasedIndexExtension<IdIndexEntry, Integer> {
   @NonNls public static final ID<IdIndexEntry, Integer> NAME = ID.create("IdIndex");
 
   private final KeyDescriptor<IdIndexEntry> myKeyDescriptor = new InlineKeyDescriptor<IdIndexEntry>() {
diff --git a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
index ce6aa2761c3f..a3193bfab59e 100644
--- a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
+++ b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
@@ -1381,7 +1381,9 @@ public final class FileBasedIndexImpl extends FileBasedIndexEx {
       if (myStorageBufferingHandler.runUpdate(false, storageUpdate)) {
         ConcurrencyUtil.withLock(myReadLock, () -> {
           if (currentFC != null) {
-            index.setIndexedStateForFile(inputId, currentFC);
+            if (!isMock(currentFC.getFile())) {
+              index.setIndexedStateForFile(inputId, currentFC);
+            }
           }
           else {
             index.resetIndexedStateForFile(inputId);
@@ -1681,7 +1683,7 @@ public final class FileBasedIndexImpl extends FileBasedIndexEx {
 
           if (file != null) {
             VirtualFile virtualFile = file.getVirtualFile();
-            if (virtualFile instanceof VirtualFileWithId) {
+            if (virtualFile instanceof VirtualFileWithId && !isMock(virtualFile)) {
               getChangedFilesCollector().getEventMerger().recordTransientStateChangeEvent(virtualFile);
             }
           }