Resolving dependencies... cabal: Could not resolve dependencies: next goal: haskelldb (user goal) rejecting: haskelldb-2.2.4, haskelldb-2.2.2, haskelldb-2.2.1, haskelldb-2.1.1, haskelldb-2.1.0, haskelldb-2.0.1.1, haskelldb-2.0.1, haskelldb-2.0 (constraint from user target requires ==0.13) trying: haskelldb-0.13 trying: base-4.9.0.0/installed-4.9... (dependency of haskelldb-0.13) next goal: mtl (dependency of haskelldb-0.13) rejecting: mtl-2.2.1, mtl-2.2.0.1, mtl-2.2, mtl-2.1.3.1, mtl-2.1.2, mtl-2.1.1, mtl-2.1, mtl-2.0.1.1, mtl-2.0.1.0, mtl-2.0.0.0 (conflict: haskelldb => mtl>=1 && <2) rejecting: mtl-1.1.1.1, mtl-1.1.1.0 (conflict: base==4.9.0.0/installed-4.9..., mtl => base<4.6) rejecting: mtl-1.1.0.2, mtl-1.1.0.1, mtl-1.1.0.0, mtl-1.0 (conflict: base==4.9.0.0/installed-4.9..., mtl => base<4.3) Dependency tree exhaustively searched.