Resolving dependencies... cabal: Could not resolve dependencies: next goal: wai-handler-devel (user goal) rejecting: wai-handler-devel-2.0.0.2, 2.0.0.1, 2.0.0, 1.3.0.6, 1.3.0.5, 1.3.0.4, 1.3.0.3, 1.3.0.2, 1.3.0.1, 1.3.0, 1.2.0.2, 1.2.0.1, 1.2.0, 1.1.0, 1.0.0, 0.4.4.1, 0.4.4, 0.4.3.1, 0.4.3, 0.4.2, 0.4.0, 0.2.1, 0.2.0.1 (global constraint requires ==0.2.0) trying: wai-handler-devel-0.2.0 trying: base-4.7.0.1/installed-e4b... (dependency of wai-handler-devel-0.2.0) next goal: hint (dependency of wai-handler-devel-0.2.0) rejecting: hint-0.4.2.3, 0.4.2.2, 0.4.2.1, 0.4.2.0, 0.4.1.0, 0.4.0.0 (conflict: wai-handler-devel => hint>=0.3.2.3 && <0.4) trying: hint-0.3.3.7 next goal: ghc-mtl (dependency of hint-0.3.3.7) rejecting: ghc-mtl-1.2.1.0, 1.2.0.0, 1.1.0.0 (conflict: hint => ghc-mtl<1.1.0.0) rejecting: ghc-mtl-1.0.1.2 (conflict: base==4.7.0.1/installed-e4b..., ghc-mtl => base<4.7) rejecting: ghc-mtl-1.0.1.1 (conflict: base==4.7.0.1/installed-e4b..., ghc-mtl => base<4.6) rejecting: ghc-mtl-1.0.1.0 (conflict: base==4.7.0.1/installed-e4b..., ghc-mtl => base>=4 && <4.4) rejecting: ghc-mtl-1.0.0.0 (conflict: hint => ghc-mtl>=1.0.1.0) Dependency tree exhaustively searched.