diff --git a/include/LIEF/PE/type_traits.hpp b/include/LIEF/PE/type_traits.hpp
index b5f6179..d353aa3 100644
--- a/include/LIEF/PE/type_traits.hpp
+++ b/include/LIEF/PE/type_traits.hpp
@@ -28,6 +28,7 @@ class Symbol;
 class ExportEntry;
 class RichEntry;
 class RelocationEntry;
+class Debug;
 
 class Import;
 class ImportEntry;