diff --git a/parse.y b/parse.y
index ab2cb603c3..ac560a8ae7 100644
--- a/parse.y
+++ b/parse.y
@@ -5950,7 +5950,7 @@ f_opt		: f_arg_asgn f_eq arg_value
                         p->cur_arg = 0;
                         p->ctxt.in_argdef = 1;
                     /*%%%*/
-                        $$ = NEW_OPT_ARG(0, assignable(p, $1, $3, &@$), &@$);
+                        $$ = NEW_OPT_ARG(assignable(p, $1, $3, &@$), &@$);
                     /*% %*/
                     /*% ripper: rb_assoc_new(get_value(assignable(p, $1)), get_value($3)) %*/
                     }
@@ -5961,7 +5961,7 @@ f_block_opt	: f_arg_asgn f_eq primary_value
                         p->cur_arg = 0;
                         p->ctxt.in_argdef = 1;
                     /*%%%*/
-                        $$ = NEW_OPT_ARG(0, assignable(p, $1, $3, &@$), &@$);
+                        $$ = NEW_OPT_ARG(assignable(p, $1, $3, &@$), &@$);
                     /*% %*/
                     /*% ripper: rb_assoc_new(get_value(assignable(p, $1)), get_value($3)) %*/
                     }
diff --git a/parser_node.h b/parser_node.h
index 886f9af7d2..c21fee6caf 100644
--- a/parser_node.h
+++ b/parser_node.h
@@ -96,7 +96,7 @@ code_loc_gen(const rb_code_location_t *loc1, const rb_code_location_t *loc2)
 #define NEW_SUPER(a,loc) NEW_NODE(NODE_SUPER,0,0,a,loc)
 #define NEW_ZSUPER(loc) NEW_NODE(NODE_ZSUPER,0,0,0,loc)
 #define NEW_ARGS_AUX(r,b,loc) NEW_NODE(NODE_ARGS_AUX,r,b,0,loc)
-#define NEW_OPT_ARG(i,v,loc) NEW_NODE(NODE_OPT_ARG,i,v,0,loc)
+#define NEW_OPT_ARG(v,loc) NEW_NODE(NODE_OPT_ARG,0,v,0,loc)
 #define NEW_KW_ARG(v,loc) NEW_NODE(NODE_KW_ARG,0,v,0,loc)
 #define NEW_POSTARG(i,v,loc) NEW_NODE(NODE_POSTARG,i,v,0,loc)
 #define NEW_ARGSCAT(a,b,loc) NEW_NODE(NODE_ARGSCAT,a,b,0,loc)