Signed word lengths and indexes

[Andrei Alexandrescu]

Don wrote:
> KennyTM~ wrote:
>> On Jun 17, 10 18:59, Don wrote:
>>> Kagamin wrote:
>>>> Don Wrote:
>>>>
>>>>> (D has introduced ANOTHER instance of this with the ridiculous >>>
>>>>> operator.
>>>>> byte b = -1;
>>>>> byte c = b >>> 1;
>>>>> Guess what c is!
>>>>> )
>>>>
>>>> :)
>>>> Well, there was issue. Wasn't it fixed?
>>>
>>> No. It's a design flaw, not a bug. I think it could only be fixed by
>>> disallowing that code, or creating a special rule to make that code do
>>> what you expect. A better solution would be to drop >>>.
>>>
>>
>> I disagree. The flaw is whether x should be promoted to 
>> CommonType!(typeof(x), int), given that the range of typeof(x >>> y) 
>> should never exceed the range of typeof(x), no matter what value y is.
> 
> The range of typeof(x & y) can never exceed the range of typeof(x), no 
> matter what value y is. Yet (byte & int) is promoted to int.
> Actually, what happens to x>>>y if y is negative?
> 
> The current rule is:
> x OP y      means
> cast(CommonType!(x,y))x OP cast(CommonType!(x,y))y
> 
> for any binary operation OP.
> How can we fix >>> without adding an extra rule?

Wait a minute. D should never allow an implicit narrowing conversion. It 
doesn't for other cases, so isn't this a simple bug?


Andrei