diff --git a/src/json.c b/src/json.c
index 442eaff..accb6cf 100644
--- a/src/json.c
+++ b/src/json.c
@@ -406,6 +406,7 @@
     }
     else
     {
+	EMSG(_(e_invarg));
 	res->v_type = VAR_SPECIAL;
 	res->vval.v_number = VVAL_NONE;
     }