An Issue I Wish To Raise Awareness On

[Atila Neves via Digitalmars-d]

On Tuesday, 18 July 2017 at 19:24:18 UTC, Jonathan M Davis wrote:
> On Tuesday, July 18, 2017 18:06:56 Atila Neves via 
> Digitalmars-d wrote:
>> On Tuesday, 18 July 2017 at 15:03:07 UTC, Kagamin wrote:
>> > On Tuesday, 18 July 2017 at 11:47:37 UTC, Petar Kirov
>> >
>> > [ZombineDev] wrote:
>> >> I think Atila was talking about this one:
>> >> struct A
>> >> {
>> >>
>> >>    ~this() {}
>> >>
>> >> }
>> >>
>> >> void main()
>> >> {
>> >>
>> >>    auto a = A();
>> >>    shared b = A();
>> >>
>> >> }
>> >
>> > This is strange. There's nothing that suggests that struct A 
>> > and its destructor is thread-safe, yet compiler assumes it 
>> > is.
>>
>> Except for a programmer explicitly and manually calling the 
>> destructor (in which case, don't), the destructor is only ever 
>> called by one thread.
>
> It could still be a problem if the struct has a member variable 
> that is a reference type, because then something else could 
> refer to that object, and if it's shared, then you would need 
> to protect it, and the operations that shared prevents should 
> still be prevented. For full-on value types, it should be a 
> non-issue though.
>
> - Jonathan M Davis

Mmm, I guess so. As Marco pointed out, it's a similar problem 
with immutable (because the compiler casts it away before calling 
the destructor).

Although I dare say that anybody writing code that depends on 
such locking and destruction when shared is unlikely to get it 
right in the first place.

Atila