[Mono-dev] CS0019 for value type != null

"Andrés G. Aragoneses" knocte at gmail.com
Tue Apr 8 06:29:59 EDT 2008

Marek Safar wrote:
> Hello Casey,
>> I've noticed that on a recent SVN build of mono, I get a CS0019 error if
>> I try to compare a value type against null. E.g.:
>>   DateTime dt;
>>   if (dt != null)
>>     Console.WriteLine(dt);
>> As far as I can tell, this is the correct behavior, since a value type
>> can't be null. I'm concerned, though, because this behavior seems to
>> have been introduced recently in SVN, AND it looks like MS's compiler
>> doesn't reject this statement (well, I haven't seen it accept it, but
>> this is existing code which apparently compiles fine under Visual
>> Studio).
> This code compiles correctly with the SVN HEAD version.

IIRC this was a design flaw that some mono devs didn't agree about, 
right? Is gmcs compiler at least reporting a warning about this? If not, 
it would be interesting to do so although MS doesn't do it (in the past 
I remember fixing some bugs in a MS.NET project because gmcs reported 
more warnings than csc!).




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