The first arg of NEW_KW_ARG macro is always 0

parse.y

@@ -11261,7 +11261,7 @@ static NODE *
 new_kw_arg(struct parser_params *p, NODE *k, const YYLTYPE *loc)
 {
     if (!k) return 0;
-    return NEW_KW_ARG(0, (k), loc);
+    return NEW_KW_ARG((k), loc);
 }
 
 static NODE *

parser_node.h

@@ -97,7 +97,7 @@ code_loc_gen(const rb_code_location_t *loc1, const rb_code_location_t *loc2)
 #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_KW_ARG(i,v,loc) NEW_NODE(NODE_KW_ARG,i,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)
 #define NEW_ARGSPUSH(a,b,loc) NEW_NODE(NODE_ARGSPUSH,a,b,0,loc)