A trait encompassing both Iterable<T>
for some fixed T
and
FromIterator<U>
for all U
(where HKT comes in). The train
could provide e.g. a default map
method producing the same kind of
the container, but with a new type parameter.
Monadic-generic programming? Can we add this without deprecating
huge swaths of the API (including Option::map
, option::collect
,
result::collect
, try!
etc.