FTBFS against ghc 8.8

[sunweaver]

@sebfisch: Hi! A while back I provided tree-monad as a Debian package. I am currently on the verge of having tree-monad removed from Debian as it fails to build under GHC 8.8.

Is there any chance that you provide a fix for this? Or shall I consider this project as "dead upstream" and have the failing src:pkg removed from Debian?

Thanks+Greets!
Mike

[sunweaver]

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=962813