Resolving dependencies... cabal: Could not resolve dependencies: next goal: speculation (user goal) rejecting: speculation-1.5.0.3, speculation-1.5.0.2, speculation-1.5.0.1, speculation-1.5, speculation-1.4.1.2, speculation-1.4.1.1, speculation-1.4.1, speculation-1.4, speculation-1.3, speculation-1.2.0.2, speculation-1.2.0.1, speculation-1.2.0.0 (constraint from user target requires ==1.1.0.0) trying: speculation-1.1.0.0 next goal: base (dependency of speculation-1.1.0.0) rejecting: base-4.9.0.0/installed-4.9... (conflict: base => ghc-prim==0.5.0.0/installed-0.5..., speculation => ghc-prim>=0.2 && <0.3) 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.