It used to require that
This PR changes that behavior, so the returned vectors from each of the
Comments are welcome. Feel free to be picky, so I can improve a bit my C++ and Rcpp skills.
`mutate(col2 = fun(col1))` on a grouped data frame calls `fun` once per group. It used to require that `fun` returns the exact same type and that was not desirable in functions that may return different (but compatible) types, such as integer and numeric. This PR changes that behaviour, so the returned vectors from each of the `fun` calls are combined using the same coercion rules than `combine` and `bind_rows`, defined in `Collecter.h`.