Route alias does not set active link class

[nolimitdev]

Version

3.0.1

Reproduction link

https://jsfiddle.net/8xrk1n9f/1279/

Steps to reproduce

Clicking at alias does not set active link class for router link referencing to About component. I think users expect this active class to work because router-link knows route definition and de facto it's alias(es). By vue-router doc aliases should behave the same way as origin route. So it should be fixed/implemented or add explicit note to https://router.vuejs.org/guide/essentials/redirect-and-alias.html#alias and/or https://router.vuejs.org/api/#active-class that active class does not work with aliases.

What is expected?

Active class should be set

What is actually happening?

Active class is not set

[posva]

Duplicate of #419