### Version 3.5.1 ### Reproduction link [https://jsfiddle.net/xkLh4njp/](https://jsfiddle.net/xkLh4njp/) ### Steps to reproduce 1. Create a Vuex store. 2. Call store.hasModule() with an array of at least 2 elements where neither module has been registered to the store. ### What is expected? store.hasModule() to return false ### What is actually happening? Error "TypeError: Cannot read property 'hasChild' of undefined" is thrown <!-- generated by vue-issues. DO NOT REMOVE -->