let extensions= (const . return $ let version = Data.Version.versionBranch System.Info.compilerVersion in if version < [6, 6] then ":set -fglasgow-exts -fallow-undecidable-instances -fallow-overlapping-instances" else if version >= [6, 8] then ":set -XTypeOperators -XKindSignatures" else "") :: String -> IO String
:def extensions extensions
:extensions