Resolving dependencies... cabal: Could not resolve dependencies: [__0] next goal: ordinal (user goal) [__0] rejecting: ordinal-0.1.1.0 (constraint from user target requires ==0.1.0.0) [__0] trying: ordinal-0.1.0.0 [__1] next goal: template-haskell (dependency of ordinal) [__1] rejecting: template-haskell-2.14.0.0/installed-2.14.0.0 (conflict: ordinal => template-haskell>=2.15.0.0) [__1] rejecting: template-haskell-2.16.0.0, template-haskell-2.15.0.0, template-haskell-2.14.0.0, template-haskell-2.13.0.0, template-haskell-2.12.0.0, template-haskell-2.11.1.0, template-haskell-2.11.0.0, template-haskell-2.10.0.0, template-haskell-2.9.0.0, template-haskell-2.8.0.0, template-haskell-2.7.0.0, template-haskell-2.6.0.0, template-haskell-2.5.0.0, template-haskell-2.4.0.1, template-haskell-2.4.0.0, template-haskell-2.3.0.1, template-haskell-2.3.0.0, template-haskell-2.2.0.0 (constraint from non-upgradeable package requires installed instance) [__1] fail (backjumping, conflict set: ordinal, template-haskell) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: template-haskell, ordinal