On Wednesday, 15 August 2012 at 05:10:02 UTC, Jonathan M Davis
wrote:
On Wednesday, August 15, 2012 07:02:25 Simen Kjaeraas wrote:
On Tue, 14 Aug 2012 22:32:58 +0200, Andrei Alexandrescu
<[email protected]> 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. And I
would expect
that anything in them is in the same boat that anything
initialized to void
is. e.g.
Type var = void;
- Jonathan M Davis
I second this.
That is actually one of the reasons why most languages with GC,
ban pointer
uses to unsafe sections, otherwise the GC would be very
restricted in the ways it could work.
Same thing about unions, as you wouldn't know which
pointer/reference is the active one without some kind of tagging.
--
Paulo
