NotNull pointers

[Walter Bright]

On 8/30/2011 7:58 AM, Christian Kamm wrote:
> I want to point out the following bug in the example, because it's *such* a
> common problem and, in my opinion, one of D's warts:
>
> Walter Bright wrote:
>>       this(P q)
>>       {
>>           assert(q);
>>           p = q;
>>       }
>
> Try
> auto d = NotNull!Object(null);
>
> you'll get a segmentation fault and not an assert. That's because
> assert(someclass) does not check if someclass is non-null at all, it
> verifies its invariant instead!
>
> All the asserts should be assert(q !is null);.

Is it really a bug? If you compile in release mode, and q is null, and you use 
!is null, you'll get a processor hardware halt. Halt or seg fault - there's not 
much practical difference.

As I've said many times, I really don't understand the fear of seg faults. The 
important thing is that the program stop running as near as possible to the 
source of the error. Whether it stops because of a software detected error or a 
hardware detected error is simply not relevant.