See <http://stackoverflow.com/questions/26027765/using-types-to-prevent-conflicting-port-numbers-in-a-list> --[[Joey]]

Needs ghc newer than 7.6.3. It may be possible to port Data.Type.Equality
and Data.Type.Bool to older versions; I got them to compile but they didn't
work right. --[[Joey]]

[[!tag user/joey]]
