Resolving dependencies... cabal: Could not resolve dependencies: trying: base-4.9.0.0/installed-4.9... (dependency of happs-tutorial-0.9.2) next goal: happstack-util (dependency of happstack-state-0.3.4) rejecting: happstack-util-6.0.3, happstack-util-6.0.2, happstack-util-6.0.0, happstack-util-0.5.0.3, happstack-util-0.5.0.2, happstack-util-0.5.0.1, happstack-util-0.5.0, happstack-util-0.4.1 (conflict: happstack-state => happstack-util>=0.3.2 && <0.4) trying: happstack-util-0.3.2 next goal: strict-concurrency (dependency of happstack-util-0.3.2) rejecting: strict-concurrency-0.2.4.1, strict-concurrency-0.2.4 (conflict: base==4.9.0.0/installed-4.9..., strict-concurrency => base>=4 && <4.6) rejecting: strict-concurrency-0.2.3 (conflict: base==4.9.0.0/installed-4.9..., strict-concurrency => base>=3 && <4.3) rejecting: strict-concurrency-0.2.2, strict-concurrency-0.2.1 (conflict: base==4.9.0.0/installed-4.9..., strict-concurrency => base>=3 && <4) rejecting: strict-concurrency-0.2, strict-concurrency-0.1 (conflict: base==4.9.0.0/installed-4.9..., strict-concurrency => base<4.3) Dependency tree exhaustively searched.