Unions destructors and GC precision

[Simen Kjaeraas]

On Wed, 15 Aug 2012 07:09:40 +0200, Jonathan M Davis <jmdavisProg at gmx.com>  
wrote:

> On Wednesday, August 15, 2012 07:02:25 Simen Kjaeraas wrote:
>> On Tue, 14 Aug 2012 22:32:58 +0200, Andrei Alexandrescu
>>
>> <SeeWebsiteForEmail at erdani.org> wrote:
>> > On 8/14/12 3:25 PM, bearophile wrote:
>> >> D2 doesn't give you that restriction, and when an union goes out of
>> >
>> >> scope it calls the destructors of all its fields:
>> > That's pretty surprising. "Major bug" doesn't begin to describe it.
>> >
>> > Unions should call no constructors and no destructors.
>>
>> That means the default case is unsafe. Should it also be an error
>> (or at least a warning) for a union containing types with destructors
>> or complex constructors not to have a defined constructor/destructor?
>
> I wouldn't expect unions to be considered @safe in the first place.  
> You're potentially reintrepreting one type as another with them.

True, when the unioned types are or contain pointers. With POD there
should be no problem.


-- 
Simen