D arithmetic problem

[Don]

davidl wrote:
> ÔÚ Wed, 03 Jun 2009 10:58:32 +0800£¬Tim Matthews 
> <tim.matthews7 at gmail.com> дµÀ:
> 
>> davidl wrote:
>>
>>> I mean the first behavior can cause problems.
>>
>> Ohh sorry.
>>
>>> I doubt any coder would try to get that result by writing that piece 
>>> of code. I ported some C# source to D, and I got this semantic 
>>> different issue.
>>>
>>
>>   It is probably mostly used for dealing with binary data but D has no 
>> other way of specifying a number that is only 1 byte except the char 
>> but that would be a misuse of the type system unless ported from 
>> c/c++. Just a few gotchas off the top of my head:
>>
>> D     C#
>> ------------
>> ubyte   Byte
>> byte    SByte
>> wchar   Char
> 
> Perhaps, it's because of my mistranslating all Byte to byte directly.

Yes. Yet there's an issue here -- EVERYONE expects 'byte' to be 
unsigned. Walter even forgot it when he did the first release of htod.
The uses for signed bytes are so rare, that any use of 'byte' is highly 
likely to be an error.

> Nonetheless, the first behavior is not impressive. I innately dislike 
> that. Because I try to deal with a type with one byte by using Or 
> operator, I get it promoted to int. That implicitly cast sounds awful.

I agree, it's bug-prone.
Ideally, we'd disallow implicit widening casts for signed types in 
logical operations. But can that be done without creating too many 
language quirks?