cast(size_t)&c != 0, but c is null

[David]

Am 15.05.2013 17:08, schrieb Artur Skawina:
> On 05/15/13 13:04, Dicebot wrote:
>> On Wednesday, 15 May 2013 at 10:31:29 UTC, David wrote:
>>>> "&c" is address of reference, no class instance. I don't know if there
>>>> is a way to get a pointer to class instance in D but I am not aware of one.
>>>
>>> A simple cast to void* should do it: cast(void*)c
> 
>    class C { auto opCast(T:void*)() { return null; } }
> 
> So - no - a simple cast to void* won't always work, as the op can be
> overloaded, even if only by accident. 
> 
> See also:
> http://forum.dlang.org/thread/mutvhrrdfzunbrhmvztp@forum.dlang.org#post-mailman.2432.1354406246.5162.digitalmars-d-learn:40puremagic.com
> and
> http://d.puremagic.com/issues/show_bug.cgi?id=8545
> 
> 
> artur
> 

Overloading cast is broken and shouldn't be in the language (imo). Why
broken? If you only want to overload cast(bool) (for if(x) which calls
if(cast(bool)x -> x.opCast!bool()) you have to overload all other
possible casts, otherwise compiler will complain that this cast is no
overloaded. Also overloading a cast doesn't really make any sense
(except the bool case), that's also the reason why I really hate
std.conv.to's new behaviour of calling opCast, this makes no sense, to!
does a conversion not a cast.