Use class template as a type

[dm via Digitalmars-d-learn]

> We have a handy dandy syntax for this:
>
> if (MyClassInt subclass = cast(MyClassInt)value) {
> 	writeln(subclass.value);
> }
>
> If it doesn't cast to said type (it will be null) that branch 
> won't execute.

Hell yeah! It's works!
Thank you!