diff --git a/include/types/sample.h b/include/types/sample.h
index 2f3cfbfc5..22dfe599d 100644
--- a/include/types/sample.h
+++ b/include/types/sample.h
@@ -28,9 +28,10 @@
 
 #include <common/chunk.h>
 #include <common/mini-clist.h>
-#include <types/arg.h>
 #include <types/proto_http.h>
 
+struct arg;
+
 /* input and output sample types */
 enum {
 	SMP_T_ANY = 0,   /* any type */