assume, assert, enforce, @safe

[Andrew Godfrey via Digitalmars-d]

On Tuesday, 5 August 2014 at 09:42:26 UTC, Ola Fosheim Grøstad 
wrote:
> But I don't think this path is all that new… so I hope Walter, 
> if he continues walking down this path, remains unrelenting and 
> keeps walking past "assert as assume" until he finds truly new 
> territory in the realm of formal methods. That could happen and 
> bring great features to D.

This! +1000!

This is what I've been feeling too: Walter is wrong - 
astonishingly wrong in fact - but in a very interesting direction 
that may have something very 'right' on the other side of it. I 
don't know what form it will take, but the example
someone gave, of keeping track of when a range is sorted vs. not 
known to be sorted, to me gives a hint of where this may lead. I 
can't quite imagine that particular example playing out, but in 
general if the compiler keeps track of properties of things then 
it could start making algorithmic-level performance decisions 
that today we always have to make by hand. To me that's 
interesting.