diff --git a/valexpr.cc b/valexpr.cc
index 487909fa..8f31e42d 100644
--- a/valexpr.cc
+++ b/valexpr.cc
@@ -1,6 +1,7 @@
 #include "valexpr.h"
 #include "error.h"
 #include "datetime.h"
+#include "debug.h"
 
 #include <vector>