if(arr) now a warning

[Steven Schveighoffer via Digitalmars-d]

On 4/29/15 4:29 AM, Iain Buclaw via Digitalmars-d wrote:
> On 29 April 2015 at 06:38, Steven Schveighoffer via Digitalmars-d
> <digitalmars-d at puremagic.com> 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
>>
>
> I disagree, and I would extend my thoughts to say that I don't think
> that the change is enough.  We should also be warning on delegates and
> associative arrays too!
>
> if (arr)  // Implicitly converted to (arr.ptr | arr.length) != 0

if(arr) simply means if(arr.ptr) != 0. Length does not come into play.

> if (dg)  // Implicitly converted to (dg.ptr | dg.funcptr) != 0

I don't know if I've ever expected that, you sure that's true? I would 
actually expect if(dg) to be equivalent to if(dg.funcptr). I have no 
idea how a dg would have a null pointer but valid funcptr.

> if (aa)  // Implicitly converted to (aa.ptr != null)

This is easily fixed when we fix aa to be a library type. We don't need 
compiler help to fix this issue (we do need compiler help to remove AA 
specialty code from the compiler, but once it's out, we can fix this 
without effort).

-Steve