Length comparison

[Lionello Lunesu]

xs0 wrote:
> Bill Baxter wrote:
>> This bit me just now:
>>
>>     if (-1 < somearray.length) {
>>     }
>>
>> Ouch.  Took me a while to figure out that that bit of code was the 
>> problem.
>>
>> Is there some way to make these kind of bugs less likely or easier to 
>> find?
> 
> It should be made illegal :) In particular:
> - comparing a negative constant with an unsigned variable
> - comparing a too large constant with a signed variable (like 
> 3_000_000_000 and something of type int)
> - setting an unsigned var to a negative constant (uint a = -1)
> 
> For other cases, comparing signed with unsigned should produce a warning 
> and, more importantly, work properly:
> 
> int a;
> uint b;
> 
> a < b  should be  a < 0 || cast(uint)a < b
> a > b  should be  a > 0 && cast(uint)a > b
> etc.etc.

http://d.puremagic.com/issues/show_bug.cgi?id=259

Could you please add your remarks to that bugzilla issue as well? 
Especially the proper implementation for mixed comparison. I agree that 
the result should at least be correct, no matter* how slow.

L.

* of course, within limits :)