/// For types that implement `Copy`, the suggestion to `Box` a variant's
/// data would require removing the trait impl. The types can of course
/// still be `Clone`, but that is worse ergonomically. Depending on the
/// For types that implement `Copy`, the suggestion to `Box` a variant's
/// data would require removing the trait impl. The types can of course
/// still be `Clone`, but that is worse ergonomically. Depending on the