That revision doesn't exist. What happened is that upstream uploaded a Cabal
file that says "x-revision: 1". Of course, the incorrect setting will come back
in as soon as we update hackage-packages.nix. Nonetheless, I'm opting for the
short-term solution here, hoping that upstream will remove the x-revision
header from Hackage soon'ish.
https://github.com/haskell/hackage-server/issues/337
6792f76706