@WG-const-eval Currently the implementation of RFC 2203 (#49147) is incomplete for e.g.
Vec::new() in array repeat expressions. I opened #65737 to track this. There, I allude to the changes to the rules for promotability that would be required to make this work; specifically,
Drop types need to be promoted in an explicit context. I know @RalfJ will have some thoughts on this as well.