Class destructors - clarify what is safe

[Brother Bill]

On Saturday, 14 February 2026 at 18:42:21 UTC, H. S. Teoh wrote:
> Basically, when something is allocated on the GC, the GC takes 
> full responsibility for managing its lifetime. User code should 
> not try to intervene.  If your object needs to be managed 
> manually, don't allocate it from the GC, use C's malloc() or 
> your own memory allocation scheme. Because of this, class dtors 
> really should not be necessary if you only allocate objects 
> from the GC.  They are only necessary when you need to manage 
> resources that are not allocated by the GC, such as OS file 
> handles, memory allocated by C's malloc(), or other such 
> things.  The dtor should only take care of cleaning up these 
> external resources, and should not try to do anything related 
> to GC-allocated objects.
>
>
> T

How does one go about determining if these are GC-allocated 
objects, or if these are external to the GC?