{switch} and {var} tag inside {case}

Version: 2.9.0

```latte
{switch 1}
    {case 1}{var $foo = ''}
{/switch}
```

This code throws exception:
```
Latte\CompileException
Arguments are not allowed in {var} in default.latte:2
```

Problem is only within {switch} tag.

Thanks ;-)

