RCArray is unsafe

[via Digitalmars-d]

On Monday, 2 March 2015 at 21:00:54 UTC, Andrei Alexandrescu 
wrote:
> On 3/2/15 12:37 PM, Walter Bright wrote:
>> On 3/1/2015 12:51 PM, Michel Fortin wrote:
>>> That's actually not enough. You'll have to block access to 
>>> global
>>> variables too:
>>>
>>>     S s;
>>>
>>>     void main() {
>>>         s.array = RCArray!T([T()]);   // s.array's refcount 
>>> is now 1
>>>         foo(s.array[0]);           // pass by ref
>>>     }
>>>     void foo(ref T t) {
>>>         s.array = RCArray!T([]);      // drop the old s.array
>>>         t.doSomething();              // oops, t is gone
>>>     }
>>
>> Thinking about it, there are many other ways this can happen. 
>> At the
>> moment, I'm stuck thinking of a solution other than requiring 
>> foo() to
>> be pure. Anyone have ideas?
>
> I have a solution (as in working implementation), but also a 
> deadline that's staring me in the face so this will have to 
> wait a couple more days.
>
> I also have a bit of an attack to const/immutable support but 
> that's less good (allows too much freedom).

"I have discovered a marvellous solution, but this post is too 
short to describe it."