Warn about using the GC

[Richard (Rikki) Andrew Cattermole]

On 15/01/2024 2:32 AM, Alexandru Ermicioi wrote:
> On Sunday, 14 January 2024 at 12:32:26 UTC, Richard (Rikki) Andrew 
> Cattermole wrote:
>>
>> But it is not a complete solution that is suitable for all scenarios.
>>
>> This is not an either/or situation. We can have both solutions as 
>> different attributes.
> 
> Perhaps there should be a `@trustedgc`, similar to what`@trusted` is in 
> safe system?
> That would fix callback issue.
> 
> Best regards,
> Alexandru.

Earlier on I considered ``@assumenogc`` instead.

It could work, but is much more explicit in code, that probably doesn't 
care. Which is why this should be the default, not opt-in.