Feature request: clone a class (similar to typedef)

[BCS]

Robert Fraser wrote:
> 
> I've _never_ run into this situation, and I doubt it's a common one. Certainly too limited, IMO, for a language feature.
> 

I run into it all the time when I want to create a new Exception type.

I practically have "class NewExp:Exception{this(char[]c){super(c);}}" 
burned into my keyboard