diff --git a/idea/idea-test-framework/src/org/jetbrains/kotlin/idea/test/ProjectDescriptorWithStdlibSources.java b/idea/idea-test-framework/src/org/jetbrains/kotlin/idea/test/ProjectDescriptorWithStdlibSources.java
index 1ecb3398ecf..6c175de1813 100644
--- a/idea/idea-test-framework/src/org/jetbrains/kotlin/idea/test/ProjectDescriptorWithStdlibSources.java
+++ b/idea/idea-test-framework/src/org/jetbrains/kotlin/idea/test/ProjectDescriptorWithStdlibSources.java
@@ -36,6 +36,8 @@ public class ProjectDescriptorWithStdlibSources extends KotlinWithJdkAndRuntimeL
         assert library != null;
         Library.ModifiableModel modifiableModel = library.getModifiableModel();
         modifiableModel.addRoot(VfsUtil.getUrlForLibraryRoot(new File("libraries/stdlib/src")), OrderRootType.SOURCES);
+        modifiableModel.addRoot(VfsUtil.getUrlForLibraryRoot(new File("core/builtins/src")), OrderRootType.SOURCES);
+        modifiableModel.addRoot(VfsUtil.getUrlForLibraryRoot(new File("core/builtins/native")), OrderRootType.SOURCES);
         modifiableModel.commit();
     }
 }