is this intended behavior?

[James Dennett]

Don Clugston wrote:
> Derek Parnell wrote:
>> On Mon, 09 Apr 2007 15:01:56 -0400, Frank Malone wrote:
>>
>>> dmd v1.010
>>>
>>> import std.stdio;
>>> void main() {
>>>         uint a = 3;
>>>         ubyte b = 3;
>>>         int c = -1;
>>>         writefln(c < a ? "true" : "false"); // outputs false
>>>         writefln(c < b ? "true" : "false"); // outputs true
>>> }
>>
>> Yes, kind of ... it is undefined behaviour ... the compiler doesn't know
>> what to do so it does something dumb instead. I believe that a warning
>> (a.k.a "error" in Walter-speak) should be issued by the compiler.
> 
> I agree.
> I think we should seriously consider the possibility that literals
> should be treated differently to variables, as regards signed-unsigned
> mismatches.
> * If the value fits in the range 0..int.max, it should be implicitly
> convertible to int, or to uint. --> 100% guaranteed safe.
> * If it is outside that range, an error should be issued, since it is
> definitely a bug.
> 
> My feeling is, that this would eliminate most of the annoying & useless
> signed/unsigned mismatch warnings, and catch many of the real bugs.

It's a shame if a language can't make the code above
do the right thing, and the right thing is simple:
-1 is less than 3, report that.  Don't try to make
comparisons convert their arguments to a common type.

With an int a and a uint b, "a<b" should give the
same result as "(a<0) || ((uint)a < b)" -- where the
conversion happens only in cases where it fits.  In
general, if the value of one side of the comparison
is out of range for the other side, the answer is
known without testing the other value.  Concretely,
for example, -3 < (uint)x for all x, and similarly
257 > (ubyte)y for all y.

-- James