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... Downloading first-class-families-0.7.0.0 Downloaded first-class-families-0.7.0.0 Starting first-class-families-0.7.0.0 Building first-class-families-0.7.0.0 Completed first-class-families-0.7.0.0