Structured bindings were not properly marked odr-used
and therefore captured in generic lambddas.
It is unclear to me if further simplification can be gained
through the allowance described in
Either way, I think this makes support for P0588 completes,
but we probably want to add test for that in a separate PR.
(and I lack confidence I understand P0588 sufficiently to assert
the completeness of our cnformance).