Vue中在<a-menu-item>下使用<router-link>报"Cannot read property '_normalized' of undefined"?

vue.esm.js?efeb:1897 TypeError: Cannot read property '_normalized' of undefined
    at normalizeLocation (vue-router.esm.js?fe87:1295)
    at VueRouter.resolve (vue-router.esm.js?fe87:2622)
    at VueComponent.render (vue-router.esm.js?fe87:423)
    at VueComponent.Vue._render (vue.esm.js?efeb:3551)
    at VueComponent.updateComponent (vue.esm.js?efeb:4069)
    at Watcher.get (vue.esm.js?efeb:4482)
    at new Watcher (vue.esm.js?efeb:4471)
    at mountComponent (vue.esm.js?efeb:4076)
    at VueComponent.Vue.$mount (vue.esm.js?efeb:9057)
    at VueComponent.Vue.$mount (vue.esm.js?efeb:11953)