Vue: Work out why extends syntax doesn't work in Navigator

[emccorson]

In the Navigator example in vue-onsenui-examples, we push a page with the following syntax:

this.$emit('push', {
  extends: page2,
  onsNavigatorProps: {
    myProp: 'This is a navigator prop'
  }
});

For some reason, the extends doesn't work with ref in VOnsNavigator, and it causes VOnsNavigator's ref to the page to be a comment instead of the page component itself.

It also gives the following warning:

[Vue warn]: Component is missing template or render function. 
  at <Anonymous key=undefined onShow=fn onPush=fn  ... > 
  at <VOnsNavigator swipeable="" page-stack= 
Array [ {…}, {…} ]
 options= 
Object { animation: "slide" }
  ... > 
  at <VOnsPage> 
  at <App>

Figure out what's going on, and if the extends syntax can no longer be used, document it.

[emccorson]

I have asked the question here: https://forum.vuejs.org/t/cant-use-component-is-on-component-with-extends-property/113523

[emccorson]

See also vuejs/core#6249.