Prevent struct going into heap memory

[Richard (Rikki) Andrew Cattermole]

On 21/07/2025 2:03 PM, Paul Backus wrote:
>     Problem is, some people believe it shouldn't. Hence this proposal to
>     give those that want that "reliability" control to make it so.
> 
> If there are people who believe that (a) the struct instance should be 
> allocated with the GC, but (b) the GC should not be responsible for its 
> cleanup, then those people are wrong, plain and simple.

Ah no, they don't like the GC introducing unreliability to the cleanup.
So they want to ban destructors in closures.

My position ends up being: you want predictability? Ok, lets solve for 
that. But the default should align with convenience.

Just disabling destructors doesn't give the predictability that you 
seek, there has to be more language checks than that.