RfC for language feature: rvalue struct

[Ola Fosheim Grøstad]

On Wednesday, 1 February 2023 at 11:26:17 UTC, FeepingCreature 
wrote:
> I mean, since it's a *reduction* in capability, it would even 
> be enough to do it as an audit step. Error on any assignment to 
> a field in the struct marked with a UDA.
>
> That can't be done before semantic assignment though...

Yes, if you can find a single location that you can hook into and 
then put all the required changes in separate (new) files to keep 
it maintainable.

(The trick is to make as few changes as possible to files that 
keep changing upstream, otherwise rebasing becomes a tedious 
chore in my experience).