diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index d060255b96..01a6ec862a 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -33,6 +33,7 @@ add_files(
     serialisation.cpp
     serialisation.hpp
     smallstack_type.hpp
+    span_type.hpp
     tinystring_type.hpp
     y_combinator.hpp
 )