diff --git a/platform/core-api/src/com/intellij/lang/Language.java b/platform/core-api/src/com/intellij/lang/Language.java
index be13e36bbb98..3619709ba28a 100644
--- a/platform/core-api/src/com/intellij/lang/Language.java
+++ b/platform/core-api/src/com/intellij/lang/Language.java
@@ -121,6 +121,7 @@ public abstract class Language extends UserDataHolderBase {
   }
 
   public static void unregisterLanguage(@NotNull Language language) {
+    IElementType.unregisterElementTypes(language);
     ReferenceProvidersRegistry.getInstance().unloadProvidersFor(language);
     ourRegisteredLanguages.remove(language.getClass());
     ourRegisteredIDs.remove(language.getID());
diff --git a/platform/core-api/src/com/intellij/psi/tree/IElementType.java b/platform/core-api/src/com/intellij/psi/tree/IElementType.java
index 46070a652ef9..9a390a82e4f4 100644
--- a/platform/core-api/src/com/intellij/psi/tree/IElementType.java
+++ b/platform/core-api/src/com/intellij/psi/tree/IElementType.java
@@ -71,6 +71,15 @@ public class IElementType {
     }
   }
 
+  public static void unregisterElementTypes(@NotNull Language language) {
+    for (int i = 0; i < ourRegistry.length; i++) {
+      IElementType type = ourRegistry[i];
+      if (type != null && type.getLanguage().equals(language)) {
+        ourRegistry[i] = null;
+      }
+    }
+  }
+
   private final short myIndex;
   @NonNls
   @NotNull