Resolving dependencies... cabal: Could not resolve dependencies: next goal: gll (user goal) rejecting: gll-0.4.0.2, gll-0.3.0.9, gll-0.3.0.10, gll-0.3.0.7, gll-0.3.0.6, gll-0.3.0.1, gll-0.3.0.0, gll-0.2.0.3, gll-0.2.0.2 (constraint from user target requires ==0.2.0.1) trying: gll-0.2.0.1 next goal: base (dependency of gll-0.2.0.1) rejecting: base-4.9.0.0/installed-4.9... (conflict: gll => base>=4.5 && <=4.8.0.0) rejecting: 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) Dependency tree exhaustively searched.