Cory McCartan

Because `seq_len(100)[-0]` returns `integer(0)` rather than `seq_len(100)`.

The population penalty inside SMC is unfortunately sensitive to both the overall population tolerance and the total number of districts. Changing the formula is probably off the table given backwards...

Causing further manipulation to potentially error out with an uninformative message.

``` cens_get_acs(tables_acs$B06011, geo="zcta") #> Error in `cens_get_acs()`: #> ! Can't combine `B06011PR_001E` and `B06011PR_001EA` .

`vec_slice` not falling back to `[` for `vctrs_list_of` types?

1

We (@christopherkenny and I) [are implementing an adjacency list `vctrs` type](https://github.com/alarm-redist/adj). We have a custom `[` that reindexes the integer "pointers." However, since our type inherits from `vctrs_list_of`, we can't...

Need to handle case when `parallel::detectCores()` is length 0