Resolving dependencies... Error: cabal: Could not resolve dependencies: [__0] trying: toml-test-drivers-1.0.0.0 (user goal) [__1] next goal: toml-parser (dependency of toml-test-drivers) [__1] rejecting: toml-parser-1.3.2.0 (conflict: toml-test-drivers => toml-parser^>=2.0.0.0) [__1] skipping: toml-parser-1.3.1.3, toml-parser-1.3.1.2, toml-parser-1.3.1.1, toml-parser-1.3.1.0, toml-parser-1.3.0.0, toml-parser-1.2.1.0, toml-parser-1.2.0.0, toml-parser-1.1.1.0, toml-parser-1.1.0.0, toml-parser-1.0.1.0, toml-parser-1.0.0.0, toml-parser-0.1.0.0 (has the same characteristics that caused the previous version to fail: excluded by constraint '^>=2.0.0.0' from 'toml-test-drivers') [__1] fail (backjumping, conflict set: toml-parser, toml-test-drivers) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: toml-test-drivers, toml-parser