diff --git a/include/ki/pclass/types/Type.h b/include/ki/pclass/types/Type.h
index df61dac..eaf3529 100644
--- a/include/ki/pclass/types/Type.h
+++ b/include/ki/pclass/types/Type.h
@@ -10,6 +10,7 @@ namespace ki
 {
 namespace pclass
 {
+	class TypeSystem;
 	class PropertyClass;
 
 	/**
diff --git a/src/pclass/ClassType.cpp b/src/pclass/ClassType.cpp
index dea5885..7d910fa 100644
--- a/src/pclass/ClassType.cpp
+++ b/src/pclass/ClassType.cpp
@@ -1,4 +1,5 @@
 #include "ki/pclass/types/ClassType.h"
+#include "ki/pclass/TypeSystem.h"
 
 namespace ki
 {