Provide isn't reactive with a single array

[ralphchristianeclipse]

Version

2.2.4

Reproduction link

http://codepen.io/anon/pen/VpyqEz?editors=1111

Steps to reproduce

Create a parent and child component

Set the provide of the parent using vuex

Inject the provide of the parent to child

What is expected?

Must be reactive

What is actually happening?

Not Reactive

[posva]

It actually doesn't depend on Vuex. It happens with plain Vue: http://codepen.io/anon/pen/EWoMLr?editors=1111

Using a single array, nothing is tracked. But if we display another injected property (in this case bar), both are updating accordingly