Fix to support MonadFail (#34)

Fixes #33 to allow library to be used with GHC-8.8.2

System/Console/Docopt/Public.hs

@@ -190,7 +190,7 @@ isPresentM :: Monad m => Arguments -> Option -> m Bool
 isPresentM args o = return $ isPresent args o
 
 {-# DEPRECATED getFirstArg "Use 'getAllArgs' instead" #-}
-getFirstArg :: Monad m => Arguments -> Option -> m String
+getFirstArg :: MonadFail m => Arguments -> Option -> m String
 getFirstArg args opt =
  let failure = fail $ "no argument given: " ++ show opt
  in case opt `M.lookup` args of

System/Console/Docopt/QQ.hs

@@ -56,7 +56,9 @@ docopt = QuasiQuoter { quoteExp = docoptExp
  , quotePat = unsupported "Pattern"
  , quoteType = unsupported "Type"
  }
- where unsupported = fail . (++ " context unsupported")
+ where unsupported :: String -> String -> Q a
+ unsupported qqType _ = do
+ fail $ (qqType ++ " context unsupported")
 
 -- | Same as 'docopt', but parses the given file instead of a literal
 -- string.

docopt.cabal

@@ -43,7 +43,7 @@ library
  System.Console.Docopt.OptParse
  System.Console.Docopt.Public
 
- build-depends: base >= 4.0 && < 5.0,
+ build-depends: base >= 4.9 && < 5.0,
  parsec >= 3.1.0,
  containers
 

stack.yaml

@@ -1,7 +1,7 @@
 # For advanced use and comprehensive documentation of the format, please see:
 # http:https://docs.haskellstack.org/en/stable/yaml_configuration/
 
-resolver: lts-7.4
+resolver: lts-16.20
 
 packages:
  - '.'