diff --git a/src/vim9.h b/src/vim9.h
index 22a3f39..9d72b96 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -759,3 +759,5 @@
 #define TVTT_DO_MEMBER	    1
 #define TVTT_MORE_SPECIFIC  2	// get most specific type for member
 
+// flags for call_def_function()
+#define DEF_USE_PT_ARGV	    1	// use the partial arguments