disabling unary "-" for unsigned types

[bearophile]

Don:
> Steven Schveighoffer:
> > If unsigned types get used far more often than they should, then they shouldn't be all over the place in the standard language 
> (i.e. size_t is used for everything size related).
> 
> Yes, that's exactly my opinion. I think size_t being unsigned is the 
> primary problem.
> 
>    You simply can't avoid using unsigned.
> 
> 
> It's also useful for when you don't think you should ever receive inputs 
> that are negative.
> That's like using double for currency. You deserve what you get.

It seems you and Steven agree with what I am saying for some months (this is just the last I have written):
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=106381

By the way, I think in C# array indexes are signed:
http://msdn.microsoft.com/en-us/library/system.collections.arraylist.item.aspx

Bye,
bearophile