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: minecraft-data-0.1.0.1 (user goal) [__1] trying: pipes-cereal-0.1.0 (dependency of minecraft-data) [__2] next goal: cereal (dependency of minecraft-data) [__2] rejecting: cereal-0.5.8.1, cereal-0.5.8.0, cereal-0.5.7.0, cereal-0.5.5.0, cereal-0.5.4.0, cereal-0.5.3.0, cereal-0.5.2.0, cereal-0.5.1.0, cereal-0.5.0.0 (conflict: pipes-cereal => cereal>=0.4 && <0.5) [__2] trying: cereal-0.4.1.1 [__3] next goal: base (dependency of minecraft-data) [__3] rejecting: base-4.12.0.0/installed-4.1... (conflict: cereal +/-split-base => base<3.0 || >=4 && <4.11) [__3] rejecting: base-4.12.0.0, base-4.11.1.0, base-4.11.0.0, base-4.10.1.0, base-4.10.0.0, base-4.9.1.0, base-4.9.0.0, base-4.8.2.0, base-4.8.1.0, base-4.8.0.0, base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1, base-4.6.0.0, base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0, base-4.3.1.0, base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0, base-4.1.0.0, base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from non-upgradeable package requires installed instance) [__3] fail (backjumping, conflict set: base, cereal, minecraft-data) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: cereal, pipes-cereal, base, minecraft-data