if(arr) now a warning

[bearophile via Digitalmars-d]

Andrei Alexandrescu:

> I have no doubt the change can find certain errors. Problem is 
> false positives. FWIW these are the changes I had to operate on 
> std.allocator to make it work with the new compiler. One per 
> 194 lines on average, all false positives:

Just fix your code Andrei Alexandrescu :-)

Bye,
bearophile