Cannot Use ControllerAs `this`
------------------------------

Can anyone explain the following scenario to me, please?

### Works

```
ng-controller="Parent as thus"

```

### Breaks

```
ng-controller="Parent as this"

```

That single letter which makes it a keyword -- which I want -- wrecks the forest.

Why is this?

P.S. I'm aware of the `vm` convention, but I find it disturbs portability of controllers/viewmodels.