Adapt to GHC 8.8.1.

Imported from https://gitlab.haskell.org/ghc/head.hackage/blob/master/patches/hpack-0.32.0.patch.

CHANGELOG.md

@@ -1,3 +1,9 @@
+## Changes in 0.33.0
+  - Support GHC 8.8.1: `fail` is no longer a part of `Monad`. Instead, it lives
+    in the `MonadFail` class. Adapting our code to this change meant changing
+    the types of exporting functions, unfortunately, hence the major version
+    bump.
+
 ## Changes in 0.32.0
   - Support Cabal 3.0
   - Switch reexported-modules to comma-separated list

src/Data/Aeson/Config/Parser.hs

@@ -32,6 +32,7 @@ module Data.Aeson.Config.Parser (
 
 import           Control.Monad
 import           Control.Applicative
+import qualified Control.Monad.Fail as Fail
 import           Control.Monad.Trans.Class
 import           Control.Monad.Trans.Writer
 import           Data.Monoid ((<>))
@@ -64,7 +65,7 @@ fromAesonPathElement e = case e of
   Aeson.Index n -> Index n
 
 newtype Parser a = Parser {unParser :: WriterT (Set JSONPath) Aeson.Parser a}
-  deriving (Functor, Applicative, Alternative, Monad)
+  deriving (Functor, Applicative, Alternative, Monad, Fail.MonadFail)
 
 liftParser :: Aeson.Parser a -> Parser a
 liftParser = Parser . lift

src/Hpack/Config.hs

@@ -5,6 +5,7 @@
 {-# LANGUAGE DeriveAnyClass #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE LiberalTypeSynonyms #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE CPP #-}

src/Hpack/Syntax/BuildTools.hs

@@ -7,6 +7,7 @@ module Hpack.Syntax.BuildTools (
 , SystemBuildTools(..)
 ) where
 
+import qualified Control.Monad.Fail as Fail
 import           Data.Text (Text)
 import qualified Data.Text as T
 import           Data.Semigroup (Semigroup(..))
@@ -53,7 +54,7 @@ instance FromValue BuildTools where
       buildToolFromString :: Text -> Parser (ParseBuildTool, DependencyVersion)
       buildToolFromString s = parseQualifiedBuildTool s <|> parseUnqualifiedBuildTool s
 
-      parseQualifiedBuildTool :: Monad m => Text -> m (ParseBuildTool, DependencyVersion)
+      parseQualifiedBuildTool :: Fail.MonadFail m => Text -> m (ParseBuildTool, DependencyVersion)
       parseQualifiedBuildTool = fmap fromCabal . cabalParse "build tool" . T.unpack
         where
           fromCabal :: D.ExeDependency -> (ParseBuildTool, DependencyVersion)
@@ -62,7 +63,7 @@ instance FromValue BuildTools where
             , DependencyVersion Nothing $ versionConstraintFromCabal version
             )
 
-      parseUnqualifiedBuildTool :: Monad m => Text -> m (ParseBuildTool, DependencyVersion)
+      parseUnqualifiedBuildTool :: Fail.MonadFail m => Text -> m (ParseBuildTool, DependencyVersion)
       parseUnqualifiedBuildTool = fmap (first UnqualifiedBuildTool) . parseDependency "build tool"
 
 newtype SystemBuildTools = SystemBuildTools {
@@ -80,7 +81,7 @@ instance FromValue SystemBuildTools where
       , parseName = T.unpack
       }
 
-      parseSystemBuildTool :: Monad m => Text -> m (String, VersionConstraint)
+      parseSystemBuildTool :: Fail.MonadFail m => Text -> m (String, VersionConstraint)
       parseSystemBuildTool = fmap fromCabal . cabalParse "system build tool" . T.unpack
         where
           fromCabal :: D.LegacyExeDependency -> (String, VersionConstraint)

src/Hpack/Syntax/Dependencies.hs

@@ -7,6 +7,7 @@ module Hpack.Syntax.Dependencies (
 , parseDependency
 ) where
 
+import qualified Control.Monad.Fail as Fail
 import           Data.Text (Text)
 import qualified Data.Text as T
 import           Data.Semigroup (Semigroup(..))
@@ -59,7 +60,7 @@ objectDependencyInfo o = objectDependency o >>= addMixins o
 dependencyInfo :: Value -> Parser DependencyInfo
 dependencyInfo = withDependencyVersion (DependencyInfo []) addMixins
 
-parseDependency :: Monad m => String -> Text -> m (String, DependencyVersion)
+parseDependency :: Fail.MonadFail m => String -> Text -> m (String, DependencyVersion)
 parseDependency subject = fmap fromCabal . cabalParse subject . T.unpack
   where
     fromCabal :: D.Dependency -> (String, DependencyVersion)

src/Hpack/Syntax/DependencyVersion.hs

@@ -25,6 +25,7 @@ module Hpack.Syntax.DependencyVersion (
 ) where
 
 import           Control.Applicative
+import qualified Control.Monad.Fail as Fail
 import           Data.Maybe
 import           Data.Scientific
 import           Data.Text (Text)
@@ -140,13 +141,13 @@ scientificToVersion n = version
       | otherwise = 0
     e = base10Exponent n
 
-parseVersionRange :: Monad m => String -> m VersionConstraint
+parseVersionRange :: Fail.MonadFail m => String -> m VersionConstraint
 parseVersionRange = fmap versionConstraintFromCabal . parseCabalVersionRange
 
-parseCabalVersionRange :: Monad m => String -> m D.VersionRange
+parseCabalVersionRange :: Fail.MonadFail m => String -> m D.VersionRange
 parseCabalVersionRange = cabalParse "constraint"
 
-cabalParse :: (Monad m, D.Parsec a) => String -> String -> m a
+cabalParse :: (Fail.MonadFail m, D.Parsec a) => String -> String -> m a
 cabalParse subject s = case D.eitherParsec s of
   Right d -> return d
   Left _ ->fail $ unwords ["invalid",  subject, show s]