Resolving dependencies... cabal: Could not resolve dependencies: next goal: helm (user goal) rejecting: helm-1.0.0, helm-0.7.1, helm-0.7.0, helm-0.6.1 (constraint from user target requires ==0.6.0) trying: helm-0.6.0 trying: base-4.9.0.0/installed-4.9... (dependency of helm-0.6.0) trying: transformers-0.5.2.0/installed-0.5... (dependency of helm-0.6.0) next goal: mtl (dependency of helm-0.6.0) rejecting: mtl-2.2.1, mtl-2.2.0.1, mtl-2.2 (conflict: helm => mtl>=2.1 && <2.2) rejecting: mtl-2.1.3.1, mtl-2.1.2 (conflict: transformers==0.5.2.0/installed-0.5..., mtl => transformers==0.3.*) rejecting: mtl-2.1.1, mtl-2.1 (conflict: base==4.9.0.0/installed-4.9..., mtl => base<4.6) rejecting: mtl-2.0.1.1, mtl-2.0.1.0, mtl-2.0.0.0, mtl-1.1.1.1, mtl-1.1.1.0, mtl-1.1.0.2, mtl-1.1.0.1, mtl-1.1.0.0, mtl-1.0 (conflict: helm => mtl>=2.1 && <2.2) Dependency tree exhaustively searched.