Resolving dependencies... Error: cabal: Could not resolve dependencies: [__0] trying: tahoe-ssk-0.3.0.0 (user goal) [__1] next goal: memory (dependency of tahoe-ssk) [__1] rejecting: memory-0.18.0 (conflict: tahoe-ssk => memory>=0.15 && <0.17) [__1] skipping: memory-0.17.0 (has the same characteristics that caused the previous version to fail: excluded by constraint '>=0.15 && <0.17' from 'tahoe-ssk') [__1] trying: memory-0.16.0 [__2] next goal: base (dependency of tahoe-ssk) [__2] rejecting: base-4.16.3.0/installed-4.16.3.0 (conflict: memory => base<4.16) [__2] skipping: base-4.19.0.0, base-4.18.1.0, base-4.18.0.0, base-4.17.2.0, base-4.17.1.0, base-4.17.0.0, base-4.16.4.0, base-4.16.3.0, base-4.16.2.0, base-4.16.1.0, base-4.16.0.0 (has the same characteristics that caused the previous version to fail: excluded by constraint '<4.16' from 'memory') [__2] rejecting: base-4.15.1.0, base-4.15.0.0, base-4.14.3.0, base-4.14.2.0, base-4.14.1.0, base-4.14.0.0, base-4.13.0.0, base-4.12.0.0, base-4.11.1.0, base-4.11.0.0, base-4.10.1.0, base-4.10.0.0, base-4.9.1.0, 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) [__2] fail (backjumping, conflict set: base, memory, tahoe-ssk) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: base, memory, tahoe-ssk