if(arr) now a warning

[Andrei Alexandrescu via Digitalmars-d]

On 4/28/15 9:38 PM, Steven Schveighoffer wrote:
> FYI, Andrei and Walter are reversing this change barring any new
> evidence it's helpful to people. Please speak up if you disagree.
>
> https://github.com/D-Programming-Language/dmd/pull/2885#issuecomment-97299912

We shouldn't frame it as black and white. It has usefulness, it also has 
drawbacks. My thesis is the drawbacks overwhelm the usefulness. -- Andrei