diff --git a/src/syntax.c b/src/syntax.c
index e99eb86..d16c220 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -4736,7 +4736,7 @@
     current_syn_inc_tag = ++running_syn_inc_tag;
     prev_toplvl_grp = curwin->w_s->b_syn_topgrp;
     curwin->w_s->b_syn_topgrp = sgl_id;
-    if (source ? do_source(eap->arg, FALSE, DOSO_NONE) == FAIL
+    if (source ? do_source(eap->arg, FALSE, DOSO_NONE, NULL) == FAIL
 				: source_runtime(eap->arg, DIP_ALL) == FAIL)
 	semsg(_(e_notopen), eap->arg);
     curwin->w_s->b_syn_topgrp = prev_toplvl_grp;