disabling unary "-" for unsigned types

[Andrei Alexandrescu]

dsimcha wrote:
> == Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
>> ulong x0;
>> static assert(!__traits(compiles, -x0));
>> uint x1;
>> static assert(!__traits(compiles, -x1));
>> ushort x2;
>> static assert(!__traits(compiles, -x2));
>> ubyte x3;
>> static assert(!__traits(compiles, -x3));
>> Sounds good?
>> Andrei
> 
> The more you bring up features to give the axe to, the more I find it funny that,
> not being a very good language lawyer, I wasn't aware that half of these features
> existed in the first place.  This is one of them.  Yes, definitely get rid of it.
>  It makes absolutely no sense.  If you want to treat your number like a signed
> int, then it should require an explicit cast.

I said the same. Walter's counter-argument is that 2's complement 
arithmetic is an inescapable reality that all coders must be aware of in 
D and its kin. Negation is really taking the two's complement of the 
thing. The fact that the type was unsigned is not of much import.

Andrei