diff --git a/hindent.cabal b/hindent.cabal
--- a/hindent.cabal
+++ b/hindent.cabal
@@ -1,5 +1,5 @@
 name:                hindent
-version:             2.3
+version:             2.4
 synopsis:            Extensible Haskell pretty printer
 description:         Extensible Haskell pretty printer. Both a library and an executable.
                      .
@@ -27,7 +27,7 @@
                      HIndent.Styles.JohanTibell
   build-depends:     base >= 4 && <5
                    , data-default
-                   , haskell-src-exts
+                   , haskell-src-exts >= 1.15.0
                    , mtl
                    , text
 
diff --git a/src/HIndent/Pretty.hs b/src/HIndent/Pretty.hs
--- a/src/HIndent/Pretty.hs
+++ b/src/HIndent/Pretty.hs
@@ -240,7 +240,8 @@
 comma = write ","
 
 -- | Write an integral.
-int :: Integral n => n -> Printer ()
+int :: Integral n
+    => n -> Printer ()
 int = write . decimal
 
 -- | Write out a string, updating the current position information.
@@ -277,15 +278,18 @@
 
 -- | Indent spaces, e.g. 2.
 getIndentSpaces :: Printer Int64
-getIndentSpaces = gets (configIndentSpaces . psConfig)
+getIndentSpaces =
+  gets (configIndentSpaces . psConfig)
 
 -- | Column limit, e.g. 80
 getColumnLimit :: Printer Int64
-getColumnLimit = gets (configMaxColumns . psConfig)
+getColumnLimit =
+  gets (configMaxColumns . psConfig)
 
 -- | Play with a printer and then restore the state to what it was
 -- before.
-sandbox :: MonadState s m => m a -> m s
+sandbox :: MonadState s m
+        => m a -> m s
 sandbox p =
   do orig <- get
      _ <- p
@@ -468,7 +472,9 @@
   swing (do pretty f)
         (lined (map pretty args))
   where (f,args) = flatten op [a]
-        flatten :: Exp NodeInfo -> [Exp NodeInfo] -> (Exp NodeInfo,[Exp NodeInfo])
+        flatten :: Exp NodeInfo
+                -> [Exp NodeInfo]
+                -> (Exp NodeInfo,[Exp NodeInfo])
         flatten (App _ f' a') b =
           flatten f' (a' : b)
         flatten f' as = (f',as)
@@ -527,7 +533,8 @@
                       Unboxed -> "#)"
                       Boxed -> ")"))
 exp (List _ es) =
-  brackets (prefixedLined "," (map pretty es))
+  brackets (prefixedLined ","
+                          (map pretty es))
 exp (LeftSection _ e op) =
   parens (depend (do pretty e
                      space)
@@ -732,8 +739,7 @@
        Nothing -> return ()
        Just derivs ->
          do newline
-            column indentSpaces
-                   (pretty derivs)
+            column indentSpaces (pretty derivs)
   where singleCons x =
           do write " ="
              indentSpaces <- getIndentSpaces
@@ -807,7 +813,8 @@
   prettyInternal x =
     case x of
       ClassA _ name types ->
-        spaced (pretty name : map pretty types)
+        spaced (pretty name :
+                map pretty types)
       InfixA{} ->
         error "FIXME: No implementation for InfixA."
       IParam{} ->
@@ -821,8 +828,7 @@
       BangedTy _ ty ->
         depend (write "!")
                (pretty ty)
-      UnBangedTy _ ty ->
-        pretty ty
+      UnBangedTy _ ty -> pretty ty
       UnpackedTy _ ty ->
         depend (write "{-# UNPACK #-} !")
                (pretty ty)
@@ -831,7 +837,7 @@
   prettyInternal x =
     case x of
       BDecls _ ds -> lined (map pretty ds)
-      IPBinds _  i -> lined (map pretty i)
+      IPBinds _ i -> lined (map pretty i)
 
 instance Pretty ClassDecl where
   prettyInternal x =
@@ -842,7 +848,8 @@
                (depend (maybeCtx ctx)
                        (do pretty h
                            (case mkind of
-                              Nothing -> return ()
+                              Nothing ->
+                                return ()
                               Just kind ->
                                 do write " :: "
                                    pretty kind)))
@@ -873,10 +880,8 @@
         depend (pretty name)
                (do space
                    indentSpaces <- getIndentSpaces
-                   braces (prefixedLined
-                             ","
-                             (map (indented indentSpaces . pretty)
-                                  fields)))
+                   braces (prefixedLined ","
+                                         (map (indented indentSpaces . pretty) fields)))
 
 instance Pretty FieldDecl where
   prettyInternal (FieldDecl _ names ty) =
@@ -941,10 +946,10 @@
     case i of
       InsDecl _ d -> pretty d
       InsType _ name ty ->
-       depend (do write "type "
-                  pretty name
-                  write " = ")
-              (pretty ty)
+        depend (do write "type "
+                   pretty name
+                   write " = ")
+               (pretty ty)
       _ -> pretty' i
 
 instance Pretty Match where
diff --git a/src/HIndent/Styles/ChrisDone.hs b/src/HIndent/Styles/ChrisDone.hs
--- a/src/HIndent/Styles/ChrisDone.hs
+++ b/src/HIndent/Styles/ChrisDone.hs
@@ -207,7 +207,9 @@
                                       column (orig + indentSpaces)
                                              (lined (map pretty args)))
   where (f,args) = flatten op [a]
-        flatten :: Exp NodeInfo -> [Exp NodeInfo] -> (Exp NodeInfo,[Exp NodeInfo])
+        flatten :: Exp NodeInfo
+                -> [Exp NodeInfo]
+                -> (Exp NodeInfo,[Exp NodeInfo])
         flatten (App _ f' a') b =
           flatten f' (a' : b)
         flatten f' as = (f',as)
@@ -277,27 +279,23 @@
                               (pretty b)
 
 -- | Is the expression "short"? Used for app heads.
-isShort :: (Pretty ast) => ast NodeInfo -> Printer Bool
+isShort :: (Pretty ast)
+        => ast NodeInfo -> Printer Bool
 isShort p =
   do line <- gets psLine
      orig <- fmap psColumn (sandbox (write ""))
      st <- sandbox (pretty p)
-     return (psLine st ==
-             line &&
-             (psColumn st <
-              orig +
-              shortName))
+     return (psLine st == line &&
+             (psColumn st < orig + shortName))
 
 -- | Is the given expression "small"? I.e. does it fit on one line and
 -- under 'smallColumnLimit' columns.
-isSmall :: MonadState PrintState m => m a -> m Bool
+isSmall :: MonadState PrintState m
+        => m a -> m Bool
 isSmall p =
   do line <- gets psLine
      st <- sandbox p
-     return (psLine st ==
-             line &&
-             psColumn st <
-             smallColumnLimit)
+     return (psLine st == line && psColumn st < smallColumnLimit)
 
 -- | Make the right hand side dependent if it's flat, otherwise
 -- newline it.
@@ -317,7 +315,8 @@
 -- | Is an expression flat?
 isFlat :: Exp NodeInfo -> Printer Bool
 isFlat (Lambda _ _ e) = isFlat e
-isFlat (App _ a b) = return (isName a && isName b)
+isFlat (App _ a b) =
+  return (isName a && isName b)
   where isName (Var{}) = True
         isName _ = False
 isFlat (InfixApp _ a _ b) =
@@ -340,21 +339,19 @@
 isOverflow p =
   do st <- sandbox p
      columnLimit <- getColumnLimit
-     return (psColumn st >
-             columnLimit)
+     return (psColumn st > columnLimit)
 
 -- | Does printing the given thing overflow column limit? (e.g. 80)
 isOverflowMax :: Printer a -> Printer Bool
 isOverflowMax p =
   do st <- sandbox p
      columnLimit <- getColumnLimit
-     return (psColumn st >
-             columnLimit + 20)
+     return (psColumn st > columnLimit + 20)
 
 -- | Is the given expression a single-liner when printed?
-isSingleLiner :: MonadState PrintState m => m a -> m Bool
+isSingleLiner :: MonadState PrintState m
+              => m a -> m Bool
 isSingleLiner p =
   do line <- gets psLine
      st <- sandbox p
-     return (psLine st ==
-             line)
+     return (psLine st == line)