Resolving dependencies... cabal: Could not resolve dependencies: [__0] trying: exception-hierarchy-0.1.0.4 (user goal) [__1] next goal: template-haskell (dependency of exception-hierarchy) [__1] rejecting: template-haskell-2.14.0.0/installed-2.14.0.0 (conflict: exception-hierarchy => template-haskell>=2.15 && <2.17) [__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: exception-hierarchy, template-haskell) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: template-haskell, exception-hierarchy