Resolving dependencies... cabal: Could not resolve dependencies: [__0] trying: liquid-ghc-prim-0.6.1 (user goal) [__1] trying: liquid-ghc-prim:setup.base-4.12.0.0/installed-4.12.0.0 (dependency of liquid-ghc-prim) [__2] trying: liquidhaskell-0.8.10.1 (dependency of liquid-ghc-prim) [__3] next goal: base (dependency of liquidhaskell) [__3] rejecting: base~>liquid-ghc-prim:setup.base-4.12.0.0/installed-4.12.0.0 (conflict: liquid-ghc-prim => ghc-prim==0.6.1, base => ghc-prim==0.5.3/installed-0.5.3) [__3] rejecting: base-4.12.0.0/installed-4.12.0.0 (multiple instances) [__3] rejecting: base-4.14.0.0, base-4.13.0.0, 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) [__3] fail (backjumping, conflict set: base, liquid-ghc-prim, liquidhaskell, liquid-ghc-prim:setup.base) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: base, liquid-ghc-prim:setup.base, liquid-ghc-prim, liquidhaskell Try running with --minimize-conflict-set to improve the error message.