Throw error if method doesn't support IPv6

There are a number of methods which does not support IPv6 (e.g. `toLong`). It would be a good idea to throw an error instead of silently getting invalid data.

Start by locating the methods that do not support IPv6, including `toLong`, and inspect how they currently handle IPv6 input. Confirm the existing behavior, then ensure unsupported methods report an error rather than returning invalid data; done means IPv6 cases no longer silently produce invalid results.

Written by the indexing model from the issue text.