Resolving dependencies... cabal: Could not resolve dependencies: next goal: syntax-example (user goal) rejecting: syntax-example-1.0.0.0 (constraint from user target requires ==0.4.0.0) trying: syntax-example-0.4.0.0 trying: base-4.9.0.0/installed-4.9... (dependency of syntax-example-0.4.0.0) next goal: syntax-printer (dependency of syntax-example-0.4.0.0) rejecting: syntax-printer-1.0.0.0, syntax-printer-0.1.0.0 (conflict: base==4.9.0.0/installed-4.9..., syntax-printer => base>=4.7 && <4.8) Dependency tree exhaustively searched.