需要帮助找出这段代码的语法错误在哪里吗

psql:accounting/tests.sql:49: ERROR:  syntax error at position 53
CONTEXT:  SQL statement "insert into accounting.account_tree as a (
            client_id,
            acct_id,
            parent_acct_id,
            path
        ) values (
            p_client_id,
            p_acct_id,
            p_parent_acct_id,
            text2ltree(ltree2text(t_parent_path) || '.' || p_acct_id)
        )
        on conflict on constraint pk_account_tree do 
            update set parent_acct_id = p_parent_acct_id
            where a.client_id = p_client_id
                and a.acct_id = p_acct_id"

完整的存储过程如下：https://github.com/beowulf1416/saas/blob/master/data/sql/postgres/accounting/procs/accounts/account_assign_parent.sql