The Cabal user's guide says: By default, Cabal will first try to satisfy dependencies with the default flag value and then, if that is not possible, with the negated value. Does this not hold for the extra-libraries? In a cabal file I have Flag docs-only default: False Library if ! flag(docs-only) extra-libraries: ole32 oleaut32 The command % cabal configure -fdocs-only completes successfully, while simple % cabal configure fails due to the unmet dependencies. Why doesn't Cabal flip the flag when it can't find those libraries? -- Roman I. Cheplyaka :: http://ro-che.info/