Compiler bug ?

[Maxim Fomin]

On Friday, 17 May 2013 at 17:08:31 UTC, Jonathan M Davis wrote:
> On Friday, May 17, 2013 11:59:38 1100110 wrote:
>> On 05/17/2013 09:35 AM, Maxim Fomin wrote:
>> > If it alwalys a bad idea, compiler should not accept such 
>> > code.
>> 
>> It is not the D way to forbid you from shooting yourself in 
>> the foot.
>> 
>> goto, catch(Throwable th), there are plenty more examples.
>
> D will stop you from shooting yourself in the foot if it can do 
> so in a way
> that doesn't actually limit you, and it does do quite a few 
> things to make it
> harder to shoot yourself in the foot, but it certainly doesn't 
> ultimately stop
> you from doing so. However, if it _never_ makes sense to 
> declare a variable
> beginning with two underscores, I don't know why the compiler 
> wouldn't forbid
> it other than the fact that it probably inserts such variables 
> prior to when
> it would do the semantic analysis to check whether variables 
> started with
> underscores, in which case, catching the user's variables that 
> start with two
> underscores while permitting the compiler's variables could get 
> tricky.
>
> - Jonathan M Davis

The only scenario when __identifiers are needed which came to my 
mind is case when working with C or os implementation. Low-level 
implementation supposed to use '__' namespace because of practice 
encouraged by ISO C and other docs to reserve space for user and 
system specific identifiers. Probably double leading underscores 
should be restricted to extern declarations.