Deprecate Foldable for Either

[Henning Thielemann]

On Fri, 3 Mar 2017, Ivan Lazar Miljenovic wrote:

> On 3 March 2017 at 06:28, David Feuer <david.feuer at gmail.com> wrote:
>> Yes. That is an excellent plan. I'd love to call it Data.List, but others
>> will disagree.
>
> Same here.
>
> I wasn't that happy with the FTP proposal when it first came up due to
> potential confusions (primarily due to naming conventions like
> "length"), but now that it's done we shouldn't go back.

We should have at least compiler warnings for those who care.