1 files changed, 12 insertions, 0 deletions
diff --git a/platform/core-impl/src/com/intellij/psi/impl/source/tree/FileElement.java b/platform/core-impl/src/com/intellij/psi/impl/source/tree/FileElement.java
index f025de75b820..76d5c421094d 100644
--- a/platform/core-impl/src/com/intellij/psi/impl/source/tree/FileElement.java
+++ b/platform/core-impl/src/com/intellij/psi/impl/source/tree/FileElement.java
@@ -19,6 +19,7 @@ package com.intellij.psi.impl.source.tree;
 import com.intellij.lang.ASTNode;
 import com.intellij.lang.FileASTNode;
 import com.intellij.openapi.util.Getter;
+import com.intellij.psi.PsiElement;
 import com.intellij.psi.impl.PsiManagerEx;
 import com.intellij.psi.impl.source.CharTableImpl;
 import com.intellij.psi.impl.source.PsiFileImpl;
@@ -28,6 +29,17 @@ import org.jetbrains.annotations.NotNull;
 
 public class FileElement extends LazyParseableElement implements FileASTNode, Getter<FileElement> {
   private volatile CharTable myCharTable = new CharTableImpl();
+  private volatile boolean myDetached;
+
+  @Override
+  protected PsiElement createPsiNoLock() {
+    return myDetached ? null : super.createPsiNoLock();
+  }
+
+  public void detachFromFile() {
+    myDetached = true;
+    clearPsi();
+  }
 
   @Override
   @NotNull