diff --git a/src/frontend/define.c b/src/frontend/define.c
index ae20c40d8..aec230655 100644
--- a/src/frontend/define.c
+++ b/src/frontend/define.c
@@ -409,13 +409,13 @@ ntharg(int num, struct pnode *args)
 {
     // fact: num >= 1 for all known invocations of ntharg()
         for (;;) {
+            if (!args)
+                return NULL;
             if (--num <= 0) {
                 if (args && args->pn_op && (args->pn_op->op_num == PT_OP_COMMA))
                     return args->pn_left;
                 return args;
             }
-            if (!args)
-                return NULL;
             if (args && args->pn_op && (args->pn_op->op_num != PT_OP_COMMA)) {
                 if (num <= 1)
                     return args;