Allocator troubles

[Luís Marques via Digitalmars-d]

On Saturday, 16 July 2016 at 16:19:11 UTC, Andrei Alexandrescu 
wrote:
> Found the problem. Currently allocatorObject allocates the 
> CAllocatorImpl object (interface implementation) straight 
> inside the given allocator, in an ouroboros fashion. 
> Subsequently, deallocateAll deallocates he CAllocatorImpl 
> itself.
>
> CAllocatorImpl!(A, Yes.indirect) allocatorObject(A)(A* pa)
> {
>     assert(pa);
>     import std.conv : emplace;
>     auto state = pa.allocate(stateSize!(CAllocatorImpl!(A, 
> Yes.indirect)));
>     import std.traits : hasMember;
>     static if (hasMember!(A, "deallocate"))
>     {
>         scope(failure) pa.deallocate(state);
>     }
>     return emplace!(CAllocatorImpl!(A, Yes.indirect))
>         (state, pa);
> }

What's the solution? I would say the solution is to use 
theAllocator instead, to allocate the CAllocatorImpl. Or maybe a 
template alias parameter that defaults to theAllocator?