Resolving dependencies... Error: cabal: Could not resolve dependencies: [__0] trying: haskell-language-server-1.10.0.0 (user goal) [__1] trying: haskell-language-server:+floskell [__2] trying: hls-floskell-plugin-1.0.2.0 (dependency of haskell-language-server +floskell) [__3] next goal: ghcide (dependency of haskell-language-server) [__3] rejecting: ghcide-1.10.0.0 (conflict: hls-floskell-plugin => ghcide^>=1.6 || ^>=1.7 || ^>=1.8 || ^>=1.9) [__3] rejecting: ghcide-1.9.1.0 (conflict: haskell-language-server => ghcide==1.10.0.0) [__3] skipping: ghcide-1.9.0.0, ghcide-1.8.0.0, ghcide-1.7.0.0, ghcide-1.6.0.1, ghcide-1.6.0.0, ghcide-1.5.0.1, ghcide-1.5.0, ghcide-1.4.2.3, ghcide-1.4.2.2, ghcide-1.4.2.0, ghcide-1.4.1.0, ghcide-1.4.0.3, ghcide-1.4.0.2, ghcide-1.4.0.1, ghcide-1.3.0.0, ghcide-1.2.0.2, ghcide-1.2.0.1, ghcide-1.2.0.0, ghcide-1.1.0.0, ghcide-1.0.0.0, ghcide-0.7.5.0, ghcide-0.7.4.0, ghcide-0.7.3.0, ghcide-0.7.2.0, ghcide-0.7.1.0, ghcide-0.7.0.0, ghcide-0.6.0.2, ghcide-0.6.0.1, ghcide-0.6.0, ghcide-0.5.0, ghcide-0.4.0, ghcide-0.3.0, ghcide-0.2.0, ghcide-0.1.0, ghcide-0.0.6, ghcide-0.0.5, ghcide-0.0.4, ghcide-0.0.3, ghcide-0.0.2, ghcide-0.0.1, ghcide-1.4.2.1 (has the same characteristics that caused the previous version to fail: excluded by constraint '==1.10.0.0' from 'haskell-language-server') [__3] fail (backjumping, conflict set: ghcide, haskell-language-server, hls-floskell-plugin) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: haskell-language-server, hls-floskell-plugin, ghcide, haskell-language-server:floskell Try running with --minimize-conflict-set to improve the error message.