From 6124d08530b718f5c61c673f211dd22895925d2d Mon Sep 17 00:00:00 2001
From: "Denis.Zhdanov" <Denis.Zhdanov@jetbrains.com>
Date: Mon, 21 Jan 2013 14:24:27 +0400
Subject: [PATCH] EA-42853 - assert: DocumentFoldingInfo.writeExternal

---
 .../folding/impl/JavaElementSignatureProvider.java         | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaElementSignatureProvider.java b/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaElementSignatureProvider.java
index 26ef1e9e13f5..1d54cca4833b 100644
--- a/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaElementSignatureProvider.java
+++ b/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaElementSignatureProvider.java
@@ -32,9 +32,12 @@ public class JavaElementSignatureProvider extends AbstractElementSignatureProvid
   @Override
   @Nullable
   public String getSignature(@NotNull final PsiElement element) {
+    PsiFile file = element.getContainingFile();
+    if (!(file instanceof PsiJavaFile)) {
+      return null;
+    }
     if (element instanceof PsiImportList) {
-      PsiFile file = element.getContainingFile();
-      if (file instanceof PsiJavaFile && element.equals(((PsiJavaFile)file).getImportList())) {
+      if (element.equals(((PsiJavaFile)file).getImportList())) {
         return "imports";
       }
       else {