DMD can implicitly convert class pointer to the bool. Is it bug or terrible feature?

[Andrei Alexandrescu]

On 11/26/13 9:39 AM, ilya-stromberg wrote:
> On Tuesday, 26 November 2013 at 17:11:38 UTC, Andrei Alexandrescu wrote:
>> On 11/26/13 8:52 AM, ilya-stromberg wrote:
>>> On Tuesday, 26 November 2013 at 16:27:27 UTC, Andrei Alexandrescu wrote:
>>>> The win of (2) itself is yet to be quantified and the breakage is
>>>> large.
>>>
>>> Excuse me, did you mean "disable shadowing global variables" or "disable
>>> shadowing class members"?
>>
>> The latter.
>
> Thanks for explanation.
> I was confused because number (2) is "disable shadowing global
> variables" and you wrote that don't want to have it. Thank you for
> explanation because I can't interpret your opinion as I want.

Apologies for writing the wrong number.

>>> If I understand everything correctly, Walter said that "Shadowing
>>> members, it's debatable". His main objection was about initializing
>>> variables in constructor, but we can add syntax sugar for this case.
>>>
>>> See also:
>>> http://forum.dlang.org/post/l6tg7n$2i7s$1@digitalmars.com
>>> http://forum.dlang.org/post/l6tjdq$2kvc$1@digitalmars.com
>>> http://d.puremagic.com/issues/show_bug.cgi?id=9801
>>
>> I think Walter agrees that we can't disallow shadowing globals. Adding
>> additional sugar is pretty much the kiss of death for the entire
>> notion of disallowing shadowing of members.
>
> Excuse me, I didn't understand you.
> The main idea:
> 1) disable shadowing class members
> 2) add additional syntax sugar for initializing variables in constructor
> as was suggested in #9801
>
> It looks like that solves problem. Is it impossible?

It is possible to the extent a lot of things are. But at this point:

(a) It's unclear whether a problem even exist, and if it does, what is 
its magnitude.

(b) There has been no convincing refutation of the alternative of doing 
nothing ("if we do nothing about this, ..."). In fact doing nothing is 
_very_ attractive from multiple angles (no work, no bugs, no 
regressions, no breakage, no surprise).

> As alternative solution, we can allow shadowing members only for
> function parameters or, maybe, only for constructor. Walter agreed that
> it's possible, "but at the cost of D becoming more of a mass of special
> cases that nobody can remember".
> http://forum.dlang.org/post/l6tjdq$2kvc$1@digitalmars.com
>
> So, syntax sugar in #9801 looks like better solution.

That sugar is already liable of causing cancer of the semicolon. And 
adding a feature that is predicated on adding sugar? Kiss of death.

Just drop this. Ten people come, on their first day using D, with eleven 
new ideas that shuffle things around a bit at the cost of breaking 
everybody's code.


Thanks,

Andrei