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: too-many-cells-0.1.2.0 (user goal) [__1] trying: transformers-0.5.5.0/installed-0.5... (dependency of too-many-cells) [__2] next goal: streaming-utils (dependency of too-many-cells) [__2] rejecting: streaming-utils-0.1.4.7 (conflict: transformers==0.5.5.0/installed-0.5..., streaming-utils => transformers>=0.4 && <0.5.3) [__2] rejecting: streaming-utils-0.1.4.6, streaming-utils-0.1.4.5, streaming-utils-0.1.4.4, streaming-utils-0.1.4.3, streaming-utils-0.1.4.2, streaming-utils-0.1.4.1, streaming-utils-0.1.4.0, streaming-utils-0.1.3.0, streaming-utils-0.1.2.2, streaming-utils-0.1.2.0, streaming-utils-0.1.1.1, streaming-utils-0.1.1.0, streaming-utils-0.1.0.1, streaming-utils-0.1.0.0 (conflict: too-many-cells => streaming-utils>=0.1.4.7) [__2] fail (backjumping, conflict set: streaming-utils, too-many-cells, transformers) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: too-many-cells, streaming-utils, transformers