Resolving dependencies... cabal: Could not resolve dependencies: [__0] trying: project-m36-0.8 (user goal) [__1] trying: ghc-8.6.3/installed-8.6.3 (dependency of project-m36) [__2] next goal: distributed-process-extras (dependency of project-m36) [__2] rejecting: distributed-process-extras-0.3.5, distributed-process-extras-0.3.2 (conflict: ghc => containers==0.6.0.1/installed-0.6.0.1, distributed-process-extras => containers>=0.4 && <0.6) [__2] rejecting: distributed-process-extras-0.3.1 (conflict: project-m36 => distributed-process-extras>=0.3.2) [__2] skipping: distributed-process-extras-0.3.0, distributed-process-extras-0.2.1.2, distributed-process-extras-0.2.1.1, distributed-process-extras-0.2.0, distributed-process-extras-0.1.1, distributed-process-extras-0.1.0 (has the same characteristics that caused the previous version to fail: excluded by constraint '>=0.3.2' from 'project-m36') [__2] fail (backjumping, conflict set: distributed-process-extras, ghc, project-m36) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: project-m36, ghc, base, distributed-process-extras Try running with --minimize-conflict-set to improve the error message.