diff --git a/idea/src/org/jetbrains/jet/lang/descriptors/MutableClassDescriptor.java b/idea/src/org/jetbrains/jet/lang/descriptors/MutableClassDescriptor.java
index 7686e45aad8..68065c8535e 100644
--- a/idea/src/org/jetbrains/jet/lang/descriptors/MutableClassDescriptor.java
+++ b/idea/src/org/jetbrains/jet/lang/descriptors/MutableClassDescriptor.java
@@ -120,7 +120,9 @@ public class MutableClassDescriptor extends MutableDeclarationDescriptor impleme
     }
 
     public void addSupertype(@NotNull JetType supertype) {
-        scopeForMemberLookup.importScope(supertype.getMemberScope());
+        if (!ErrorUtils.isErrorType(supertype)) {
+            scopeForMemberLookup.importScope(supertype.getMemberScope());
+        }
         supertypes.add(supertype);
     }