Allocator-aware @safe reference counting is still not possible

[Dukc]

On Sunday, 25 September 2022 at 14:52:09 UTC, Paul Backus wrote:
> On Sunday, 25 September 2022 at 14:45:38 UTC, Dukc wrote:
>> A language change like that is ideal in the long term. My 
>> point, however, is that we're not blocked on waiting for one. 
>> An allocator-enabled safe reference counter is possible with 
>> the present language (except perhaps for some yet-undiscovered 
>> issue). The downside that the deallocators will have to be 
>> reviewed against not only causing UB by themselves, but also 
>> against leaking a pointer so that it can be reached by `@safe` 
>> code.
>
> Well, of course, if you are willing to write unsound `@trusted` 
> code, anything can be made `@safe`. :)

The `SafeRefCounted` destructor wouldn't be any less sound that 
it's now. If `free` did something it's not supposed to, the 
`@trusted` attribute on the destructor would be invalid. It isn't 
any different with a custom deallocator.