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: userid-0.1.3.3 (user goal) [__1] trying: web-routes-th-0.22.6.3 (dependency of userid) [__2] trying: text-1.2.3.1/installed-1.2... (dependency of web-routes-th) [__3] next goal: template-haskell (dependency of web-routes-th) [__3] rejecting: template-haskell-2.14.0.0/installed-2.1... (conflict: web-routes-th => template-haskell<2.14) [__3] rejecting: template-haskell-2.14.0.0, template-haskell-2.13.0.0, template-haskell-2.12.0.0, template-haskell-2.11.1.0, template-haskell-2.11.0.0, template-haskell-2.10.0.0, template-haskell-2.9.0.0, template-haskell-2.8.0.0, template-haskell-2.7.0.0, template-haskell-2.6.0.0, template-haskell-2.5.0.0, template-haskell-2.4.0.1, template-haskell-2.4.0.0, template-haskell-2.3.0.1, template-haskell-2.3.0.0, template-haskell-2.2.0.0 (constraint from non-upgradeable package requires installed instance) [__3] fail (backjumping, conflict set: template-haskell, web-routes-th) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: template-haskell, pretty, text, boomerang, base, userid, web-routes-th