Resolving dependencies... cabal: Could not resolve dependencies: trying: happstack-helpers-0.56 (user goal) trying: base-4.8.1.0/installed-4f7... (dependency of happstack-helpers-0.56) next goal: happstack-data (dependency of happstack-helpers-0.56) rejecting: happstack-data-6.0.1, 6.0.0 (conflict: happstack-helpers => happstack-data>=0.3 && <0.6) trying: happstack-data-0.5.0.3 next goal: happstack-util (dependency of happstack-data-0.5.0.3) rejecting: happstack-util-6.0.3, 6.0.2, 6.0.0 (conflict: happstack-data => happstack-util>=0.5 && <0.6) trying: happstack-util-0.5.0.3 next goal: strict-concurrency (dependency of happstack-util-0.5.0.3) rejecting: strict-concurrency-0.2.4.1, 0.2.4 (conflict: base==4.8.1.0/installed-4f7..., strict-concurrency => base>=4 && <4.6) rejecting: strict-concurrency-0.2.3 (conflict: base==4.8.1.0/installed-4f7..., strict-concurrency => base>=3 && <4.3) rejecting: strict-concurrency-0.2.2, 0.2.1 (conflict: base==4.8.1.0/installed-4f7..., strict-concurrency => base>=3 && <4) rejecting: strict-concurrency-0.2, 0.1 (conflict: base==4.8.1.0/installed-4f7..., strict-concurrency => base<4.3) Backjump limit reached (change with --max-backjumps).