Use-after-move UB in lenses

[Siapran]

Observed in optional.hpp, using bind_opt in a lager::set caused a use-after-move UB, resulting in a default constructed whole being written back.

[arximboldi]

Hmmm :thinking: Do you know how to fix it?

[Siapran]

I wasn't able to do much past just disabling moves for whole in the case where it has a value...