多重继承下调用this.super会出现循环引用错误 about thinkjs HOT 7 CLOSED

export default class extends think.controller.rest {
    /**
     * init
     * @param  {Object} http []
     * @return {}      []
     */
    init(http) {
        super.init(http);
    }

    /**
     * before magic method
     * @return {Promise} []
     */
    __before() {

    }

    async getAction() {
        let User = this.model('user');
        let query = this.http.query;
        try {

            let is = await User.checkExist(query.username);
            if (is) {
                this.success({msg: 'have'});
            } else {
                let id = await User.add(query);
                console.log(id)
                this.success({id: id});
            }
        } catch (e) {
            this.fail(e.message);
        }

    }

}

// XXX: 模型操作add关键字会引起循环引用
    add(query) {
        return this.add({
            username: query.username,
            password: think.md5(query.password),
            status: STATUS.ACTIVATED,
            timestamp: new Date().getTime()
        })
    }

export default class extends think.controller.rest {
    /**
     * init
     * @param  {Object} http []
     * @return {}      []
     */
    init(http) {
        super.init(http);
    }

    /**
     * before magic method
     * @return {Promise} []
     */
    __before() {

    }

    async getAction() {
        let User = this.model('user');
        let query = this.http.query;
        try {

            let is = await User.checkExist(query.username);
            if (is) {
                this.success({msg: 'have'});
            } else {
                let id = await User.add(query);
                console.log(id)
                this.success({id: id});
            }
        } catch (e) {
            this.fail(e.message);
        }

    }

}