silence redundant import warnings with ghc 8.4

bin/hledger-check.hs

@@ -76,6 +76,8 @@ hledger-check "(assets:overdraft  < £2000) ==> (*assets:checking  == £0)"
 "If I have taken money from my overdraft, then I must have no money in
 my checking account (including subaccounts)."
 -}
+{-# LANGUAGE CPP #-}
+
 module Main where
 
 import Control.Arrow (first)
@@ -88,7 +90,9 @@ import Data.Functor.Identity (Identity(..))
 import Data.List (foldl', groupBy, intercalate, nub, sortOn)
 import Data.List.NonEmpty (NonEmpty(..), nonEmpty, toList)
 import Data.Maybe (fromMaybe, mapMaybe)
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid ((<>))
+#endif
 import Data.Time.Calendar (toGregorian)
 import Data.Time.Calendar.OrdinalDate (mondayStartWeek, sundayStartWeek, toOrdinalDate)
 import Data.Text (isPrefixOf, pack, unpack)

hledger-lib/Hledger/Data/AccountName.hs

@@ -1,4 +1,6 @@
-{-# LANGUAGE NoMonomorphismRestriction, OverloadedStrings #-}
+{-# LANGUAGE NoMonomorphismRestriction #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 {-|
 
 'AccountName's are strings like @assets:cash:petty@, with multiple
@@ -10,7 +12,9 @@ hierarchy.
 module Hledger.Data.AccountName
 where
 import Data.List
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Text (Text)
 import qualified Data.Text as T
 import Data.Tree

hledger-lib/Hledger/Data/AutoTransaction.hs

@@ -1,4 +1,6 @@
-{-# LANGUAGE OverloadedStrings, ViewPatterns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE CPP #-}
 {-|
 
 This module provides utilities for applying automated transactions like
@@ -18,7 +20,9 @@ module Hledger.Data.AutoTransaction
 where
 
 import Data.Maybe
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid ((<>))
+#endif
 import Data.Time.Calendar
 import qualified Data.Text as T
 import Hledger.Data.Types

hledger-lib/Hledger/Data/Commodity.hs

@@ -8,12 +8,15 @@ are thousands separated by comma, significant decimal places and so on.
 -}
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.Data.Commodity
 where
 import Data.List
 import Data.Maybe (fromMaybe)
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import qualified Data.Text as T
 import Test.HUnit
 -- import qualified Data.Map as M

hledger-lib/Hledger/Data/Journal.hs

@@ -84,7 +84,9 @@ import Data.List
 import Data.List.Extra (groupSort)
 -- import Data.Map (findWithDefault)
 import Data.Maybe
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Ord
 import qualified Data.Semigroup as Sem
 import Data.Text (Text)

hledger-lib/Hledger/Data/Posting.hs

@@ -8,6 +8,7 @@ look up the date or description there.
 -}
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.Data.Posting (
   -- * Posting
@@ -59,7 +60,9 @@ where
 import Data.List
 import Data.Maybe
 import Data.MemoUgly (memo)
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Ord
 import Data.Text (Text)
 import qualified Data.Text as T

hledger-lib/Hledger/Query.hs

@@ -6,6 +6,7 @@ transactions..)  by various criteria, and a SimpleTextParser for query expressio
 -}
 
 {-# LANGUAGE DeriveDataTypeable, OverloadedStrings, ViewPatterns #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.Query (
   -- * Query and QueryOpt
@@ -49,7 +50,9 @@ import Data.Data
 import Data.Either
 import Data.List
 import Data.Maybe
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid ((<>))
+#endif
 -- import Data.Text (Text)
 import qualified Data.Text as T
 import Data.Time.Calendar

hledger-lib/Hledger/Read/Common.hs

@@ -33,7 +33,9 @@ import Data.List.NonEmpty (NonEmpty(..))
 import Data.List.Split (wordsBy)
 import Data.Maybe
 import qualified Data.Map as M
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Text (Text)
 import qualified Data.Text as T
 import Data.Time.Calendar

hledger-lib/Hledger/Read/JournalReader.hs

@@ -79,7 +79,9 @@ import Control.Monad
 import Control.Monad.Except (ExceptT(..), runExceptT, throwError)
 import Control.Monad.State.Strict
 import qualified Data.Map.Strict as M
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Text (Text)
 import Data.String
 import Data.List

hledger-lib/Hledger/Utils/Text.hs

@@ -2,6 +2,7 @@
 -- There may be better alternatives out there.
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.Utils.Text
  --  (
@@ -57,7 +58,9 @@ where
 
 -- import Data.Char
 import Data.List
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Text (Text)
 import qualified Data.Text as T
 -- import Text.Parsec

hledger-ui/Hledger/UI/AccountsScreen.hs

@@ -2,6 +2,7 @@
 
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.UI.AccountsScreen
  (accountsScreen
@@ -18,7 +19,9 @@ import Control.Monad
 import Control.Monad.IO.Class (liftIO)
 import Data.List
 import Data.Maybe
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import qualified Data.Text as T
 import Data.Time.Calendar (Day)
 import qualified Data.Vector as V

hledger-ui/Hledger/UI/ErrorScreen.hs

@@ -1,6 +1,7 @@
 -- The error screen, showing a current error condition (such as a parse error after reloading the journal)
 
 {-# LANGUAGE OverloadedStrings, FlexibleContexts, RecordWildCards #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.UI.ErrorScreen
  (errorScreen
@@ -14,7 +15,9 @@ import Brick
 -- import Brick.Widgets.Border (borderAttr)
 import Control.Monad
 import Control.Monad.IO.Class (liftIO)
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Time.Calendar (Day)
 import Graphics.Vty (Event(..),Key(..))
 import Text.Megaparsec.Compat

hledger-ui/Hledger/UI/RegisterScreen.hs

@@ -1,6 +1,7 @@
 -- The account register screen, showing transactions in an account, like hledger-web's register.
 
 {-# LANGUAGE OverloadedStrings, FlexibleContexts, RecordWildCards #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.UI.RegisterScreen
  (registerScreen
@@ -14,7 +15,9 @@ import Control.Monad
 import Control.Monad.IO.Class (liftIO)
 import Data.List
 import Data.List.Split (splitOn)
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Data.Maybe
 import qualified Data.Text as T
 import Data.Time.Calendar

hledger-ui/Hledger/UI/Theme.hs

@@ -9,6 +9,7 @@
 
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.UI.Theme (
    defaultTheme
@@ -19,7 +20,9 @@ module Hledger.UI.Theme (
 
 import qualified Data.Map as M
 import Data.Maybe
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Graphics.Vty
 import Brick
 import Brick.Widgets.Border

hledger-ui/Hledger/UI/TransactionScreen.hs

@@ -1,6 +1,7 @@
 -- The transaction screen, showing a single transaction's general journal entry.
 
 {-# LANGUAGE OverloadedStrings, TupleSections, RecordWildCards #-} -- , FlexibleContexts
+{-# LANGUAGE CPP #-}
 
 module Hledger.UI.TransactionScreen
  (transactionScreen
@@ -11,7 +12,9 @@ where
 import Control.Monad
 import Control.Monad.IO.Class (liftIO)
 import Data.List
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import qualified Data.Text as T
 import Data.Time.Calendar (Day)
 import Graphics.Vty (Event(..),Key(..))

hledger-ui/Hledger/UI/UIUtils.hs

@@ -2,6 +2,7 @@
 {- | Rendering & misc. helpers. -}
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.UI.UIUtils
 where
@@ -16,7 +17,9 @@ import Brick.Widgets.List
 import Control.Monad.IO.Class
 import Data.List
 import Data.Maybe
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 import Graphics.Vty (Event(..),Key(..),Modifier(..),Color,Attr,currentAttr)
 import Lens.Micro.Platform
 import System.Environment

hledger-web/Import.hs

@@ -17,4 +17,6 @@ import           Settings             as Import
 import           Settings.Development as Import
 import           Settings.StaticFiles as Import
 
+#if !(MIN_VERSION_base(4,11,0))
 import           Data.Monoid          as Import ((<>))
+#endif

hledger/Hledger/Cli/Commands.hs

@@ -4,6 +4,7 @@ hledger's built-in commands, and helpers for printing the commands list.
 
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.Cli.Commands (
    findCommand
@@ -38,7 +39,9 @@ where
 import Control.Monad
 import Data.List
 import Data.List.Split (splitOn)
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid ((<>))
+#endif
 import Data.String.Here
 import Data.Text (Text)
 import qualified Data.Text as T

hledger/Hledger/Cli/Commands/Accounts.hs

@@ -11,6 +11,7 @@ The @accounts@ command lists account names:
 -}
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.Cli.Commands.Accounts (
   accountsmode
@@ -19,7 +20,9 @@ module Hledger.Cli.Commands.Accounts (
 ) where
 
 import Data.List
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid
+#endif
 -- import Data.Text (Text)
 import qualified Data.Text as T
 import System.Console.CmdArgs.Explicit as C

hledger/Hledger/Cli/Commands/Rewrite.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE OverloadedStrings, LambdaCase, DeriveTraversable, ViewPatterns, QuasiQuotes #-}
+{-# LANGUAGE CPP #-}
 
 module Hledger.Cli.Commands.Rewrite (
   rewritemode
@@ -6,7 +7,9 @@ module Hledger.Cli.Commands.Rewrite (
 ) 
 where
 
+#if !(MIN_VERSION_base(4,11,0))
 import Control.Monad.Writer
+#endif
 import Data.List (sortOn, foldl')
 import Data.String.Here
 import qualified Data.Text as T

site/hakyll-std/TableOfContents.hs

@@ -1,6 +1,8 @@
-{-# LANGUAGE OverloadedStrings #-}
 -- from https://github.com/blaenk/blaenk.github.io
 
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
+
 module TableOfContents (
   tableOfContents,
   ignoreTOC,
@@ -13,7 +15,9 @@ import Text.Pandoc.Walk (walk, query)
 
 import Data.List (groupBy)
 import Data.Tree (Forest, Tree(Node))
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid ((<>), mconcat)
+#endif
 import Data.Function (on)
 import Data.Maybe (fromMaybe)
 

tools/pandoc-add-toc.hs

@@ -10,12 +10,15 @@
 -- Based on code from https://github.com/blaenk/blaenk.github.io
 
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 
 import Data.Char (isDigit)
 import Data.List (groupBy)
 import Data.List.Split
 import Data.Tree (Forest, Tree(Node))
+#if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid ((<>), mconcat)
+#endif
 import Data.Function (on)
 import Data.Maybe (fromMaybe)
 import Safe