WTF does "Enforcement failed" actually mean?

[John Colvin via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 07:08:00 UTC, Russel Winder wrote:
> On Wed, 2015-09-30 at 23:35 -0700, Ali Çehreli via 
> Digitalmars-d-learn wrote:
>> On 09/30/2015 10:46 PM, Russel Winder via Digitalmars-d-learn 
>> wrote:
>> > [...]
>> 
>> It's coming from the following no-message enforce():
>> 
>>              enforce(!r.empty);
>> 
>> 
>> https://github.com/D-Programming-Language/phobos/blob/master/std/algo
>> rithm/iteration.d#L2481
>> 
>> You are using the no-seed version of reduce(), which uses the 
>> first element as seed, which means that the range cannot be 
>> empty.
>
> Well that explanation (*) makes it abundantly clear that the 
> error reporting from this part of Phobos is distinctly 
> substandard, let alone below par.
>
>
> (*) Which is clear and informative!

Bug report? Then it'll get fixed.