Warning: The install command is a part of the legacy v1 style of cabal usage.

Please switch to using either the new project style and the new-install
command or the legacy v1-install alias as new-style projects will become the
default in the next version of cabal-install. Please file a bug if you cannot
replicate a working v1- use case with the new-style commands.

For more information, see: https://wiki.haskell.org/Cabal/NewBuild

Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: acme-everything-2018.11.18 (user goal)
[__1] next goal: ztail (dependency of acme-everything)
[__1] rejecting: ztail-1.2.0.2, ztail-1.2.0.1, ztail-1.2, ztail-1.1,
ztail-1.0.2, ztail-1.0.1, ztail-1.0 (does not contain library, which is
required by acme-everything)
[__1] fail (backjumping, conflict set: acme-everything, ztail)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: base, acme-everything, ztail