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: distributed-process-p2p-0.1.5.0 (user goal) [__1] trying: network-transport-tcp-0.6.0 (dependency of distributed-process-p2p) [__2] trying: network-transport-0.5.2 (dependency of distributed-process-p2p) [__3] trying: distributed-process-0.7.4 (dependency of distributed-process-p2p) [__4] next goal: stm (dependency of distributed-process) [__4] rejecting: stm-2.5.0.0/installed-2.5..., stm-2.5.0.0 (conflict: distributed-process => stm>=2.4 && <2.5) [__4] trying: stm-2.4.5.1 [__5] next goal: base (dependency of distributed-process-p2p) [__5] rejecting: base-4.12.0.0/installed-4.1... (conflict: stm => base>=4.3 && <4.12) [__5] 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) [__5] fail (backjumping, conflict set: base, distributed-process-p2p, stm) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: distributed-process, stm, base, distributed-process-p2p, network-transport, network-transport-tcp