diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/ModuleDescriptorImpl.java b/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/ModuleDescriptorImpl.java
index e935412fdfa..ba8a6a70e67 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/ModuleDescriptorImpl.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/ModuleDescriptorImpl.java
@@ -74,6 +74,13 @@ public class ModuleDescriptorImpl extends DeclarationDescriptorImpl implements C
         return moduleConfiguration;
     }
 
+    @Inject
+    public ModuleDescriptorImpl setModuleConfiguration(@NotNull ModuleConfiguration moduleConfiguration) {
+        assert this.moduleConfiguration == null : "Trying to set module configuration twice for " + this;
+        this.moduleConfiguration = moduleConfiguration;
+        return this;
+    }
+
     @NotNull
     @Override
     public List<ImportPath> getDefaultImports() {
@@ -86,12 +93,6 @@ public class ModuleDescriptorImpl extends DeclarationDescriptorImpl implements C
         return platformToKotlinClassMap;
     }
 
-    @Inject
-    public ModuleDescriptorImpl setModuleConfiguration(@NotNull ModuleConfiguration moduleConfiguration) {
-        this.moduleConfiguration = moduleConfiguration;
-        return this;
-    }
-
     public NamespaceDescriptorImpl getRootNamespaceDescriptorImpl() {
         return (NamespaceDescriptorImpl) rootNamepsace;
     }