Attributes lost in TypeInfo, please advise

[Steven Schveighoffer via Digitalmars-d]

On 2/12/15 11:01 PM, Jakob Ovrum wrote:
> On Thursday, 12 February 2015 at 12:59:39 UTC, Steven Schveighoffer wrote:
>> I think given the necessity of the above (which was not discussed or
>> noticed in that bug report), we should add a way to call the true
>> destructor properly in the compiler.
>>
>
> I think these do the right thing with only marginal overhead:
>
> ---
> void destructRecurse(S)(ref S s)
>      if (is(S == struct))
> {
>      static if (__traits(hasMember, S, "__dtor"))
>          s.__dtor();
>
>      foreach_reverse (ref field; s.tupleof)
>      {
>          alias Field = typeof(field);
>          static if (is(Field == struct) && hasElaborateDestructor!Field)
>              destructRecurse(field);
>      }
> }
>
> void postblitRecurse(S)(ref S s)
>      if (is(S == struct))
> {
>      foreach (ref field; s.tupleof)
>      {
>          alias Field = typeof(field);
>          static if (is(Field == struct) &&
> hasElaborateCopyConstructor!Field)
>              postblitRecurse(field);
>      }
>
>      static if (__traits(hasMember, S, "__postblit"))
>          s.__postblit();
> }
> ---
> I notice now it is missing proper handling of fixed-length arrays: I'll
> add that. Anything else missing?
>
> Efficiency-wise they should at least be a lot better than the status quo
> - two indirect calls. For absolutely optimal performance it relies on
> the inliner, but if it is demonstrated to be a problem compared to the
> compiler-generated solution, it could always generate optimal code with
> some hands-on string mixins :)
>
> I am aware that std.traits is not available in object_.d - the
> hasElaborate* templates are fairly simple and easy to reimplement.

Thanks, but I wonder, aren't we simply duplicating what the compiler 
does? It seems kind of wasteful to have 2 identical functions. Plus, if 
any behavior changes, I'd rather have one place to change it. Last thing 
we need is subtle differences between builtin destruction and explicit 
destruction.

I really think either the compiler should be redirected to call this 
function (ideal) or we should be able to call the compiler function 
directly.

-Steve