Resolving dependencies... cabal: Could not resolve dependencies: next goal: computational-algebra (user goal) rejecting: computational-algebra-0.3.0.0, 0.2.0.0, 0.1.3.6, 0.1.3.5, 0.1.3.1, 0.1.3.0, 0.1.2.0, 0.1.1.0, 0.1.0.1, 0.1.0.0, 0.0.3.2, 0.0.3.1, 0.0.3.0, 0.0.2.0, 0.0.1.1 (global constraint requires ==0.0.1.0) trying: computational-algebra-0.0.1.0 trying: base-4.8.1.0/installed-4f7... (dependency of computational-algebra-0.0.1.0) trying: parsec-3.1.9 (dependency of computational-algebra-0.0.1.0) trying: text-1.2.1.3 (dependency of parsec-3.1.9) trying: deepseq-1.4.1.1/installed-8fb... (dependency of text-1.2.1.3) trying: mtl-2.2.1 (dependency of parsec-3.1.9) next goal: lens (dependency of computational-algebra-0.0.1.0) rejecting: lens-4.13, 4.12.3, 4.12.2, 4.12.1, 4.12, 4.11.1, 4.11, 4.10, 4.9.1, 4.9, 4.8, 4.7.0.1, 4.7, 4.6.0.1, 4.6, 4.5, 4.4.0.2, 4.4.0.1, 4.4, 4.3.3, 4.3.2, 4.3.1, 4.3, 4.2, 4.1.2.1, 4.1.2, 4.1.1, 4.1, 4.0.7, 4.0.6, 4.0.5, 4.0.4, 4.0.3, 4.0.2, 4.0.1, 4.0 (conflict: computational-algebra => lens==3.*) rejecting: lens-3.10.3, 3.10.2, 3.10.1, 3.10.0.1, 3.10 (conflict: base==4.8.1.0/installed-4f7..., lens => base>=4.4 && <4.7) rejecting: lens-3.9.2, 3.9.1, 3.9.0.3, 3.9.0.2, 3.9.0.1, 3.9, 3.8.7.3, 3.8.7.2, 3.8.7.1, 3.8.7, 3.8.6, 3.8.5, 3.8.4, 3.8.3, 3.8.2, 3.8.1, 3.8.0.2, 3.8.0.1, 3.8 (conflict: deepseq => array==0.5.1.0/installed-d42..., lens => array>=0.3.0.2 && <0.5) rejecting: lens-3.7.6, 3.7.5, 3.7.4, 3.7.3, 3.7.2, 3.7.1.2, 3.7.1.1, 3.7.1, 3.7.0.2, 3.7.0.1 (conflict: mtl==2.2.1, lens => mtl>=2.0.1 && <2.2) rejecting: lens-3.7, 3.6.0.4, 3.6.0.3, 3.6.0.2, 3.6.0.1, 3.6, 3.5.1, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0.6, 3.0.5, 3.0.4, 3.0.3, 3.0.2, 3.0.1, 3.0 (conflict: mtl==2.2.1, lens => mtl>=2.1.1 && <2.2) rejecting: lens-2.9, 2.8, 2.7.0.1, 2.7, 2.6.1, 2.6, 2.5, 2.4.0.2, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9.1, 1.9, 1.8, 1.7.1, 1.7, 1.6, 1.5, 1.4.1, 1.4, 1.3.1, 1.3, 1.2, 1.1.1, 1.1, 1.0.3, 1.0.2, 1.0.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 (conflict: computational-algebra => lens==3.*) Dependency tree exhaustively searched.