Destructors can't be @nogc?

[Mike Parker]

On Sunday, 25 July 2021 at 00:15:30 UTC, Jim wrote:

>
> But I think `destroy()` not being @nogc even though the 
> destructor is tagged @nogc is a bug, and it should be fixed. 
> Because it is problematic behaviour even if we limit the usage 
> of @nogc.

It's not a bug. The destructor being tagged has nothing to do 
with it. destroy can call @nogc destructors just fine. It just 
can't itself be called in @nogc functions.

As Paul described, the root reason is down to rt_finalize. Were 
it marked @nogc, then you could call destroy from @nogc code, but 
you wouldn't be able to call destructors that aren't @nogc---an 
even worse situation, IMO.

I think it's worth looking into how we can make destroy (or an 
alternative) available in @nogc functions as an enhancement. It's 
possible for extern(C) functions to be templated, so that might 
be a potential path. With a templated rt_finalize (or an 
alternative) then perhaps attribute inference could kick in and 
make destroy (or an alternative) callable in both @nogc functions 
and non.