less OverlappingInstances noise

2015-12-27 17:54:29 +01:00 · 2015-12-27 17:54:29 +01:00 · 79d4f944a4
commit 79d4f944a4
parent 41d5a5d943
33 changed files with 199 additions and 259 deletions
--- a/servant-blaze/include/overlapping-compat.h
+++ b/servant-blaze/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-blaze/servant-blaze.cabal
+++ b/servant-blaze/servant-blaze.cabal
@ -30,3 +30,4 @@ library
                     , blaze-html
  hs-source-dirs:      src
  default-language:    Haskell2010
+  include-dirs: include
--- a/servant-blaze/src/Servant/HTML/Blaze.hs
+++ b/servant-blaze/src/Servant/HTML/Blaze.hs
@ -3,10 +3,8 @@
 {-# LANGUAGE FlexibleInstances     #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE OverloadedStrings     #-}
-#if !MIN_VERSION_base(4,8,0)
-{-# LANGUAGE OverlappingInstances  #-}
-#endif

+#include "overlapping-compat.h"
 -- | An @HTML@ empty data type with `MimeRender` instances for @blaze-html@'s
 -- `ToMarkup` class and `Html` datatype.
 -- You should only need to import this module for it's instances and the
@ -29,17 +27,9 @@ data HTML deriving Typeable
 instance Accept HTML where
    contentType _ = "text" M.// "html" M./: ("charset", "utf-8")

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
-         ToMarkup a => MimeRender HTML a where
+instance OVERLAPPABLE_ ToMarkup a => MimeRender HTML a where
    mimeRender _ = renderHtml . toHtml

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
-         MimeRender HTML Html where
+instance OVERLAPPING_ MimeRender HTML Html where
    mimeRender _ = renderHtml

--- a/servant-cassava/include/overlapping-compat.h
+++ b/servant-cassava/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-cassava/servant-cassava.cabal
+++ b/servant-cassava/servant-cassava.cabal
@ -27,3 +27,4 @@ library
                     , vector
  hs-source-dirs:      src
  default-language:    Haskell2010
+  include-dirs: include
--- a/servant-client/include/overlapping-compat.h
+++ b/servant-client/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-client/servant-client.cabal
+++ b/servant-client/servant-client.cabal
@ -49,6 +49,7 @@ library
  hs-source-dirs: src
  default-language: Haskell2010
  ghc-options: -Wall
+  include-dirs: include

 test-suite spec
  type: exitcode-stdio-1.0
--- a/servant-client/src/Servant/Client.hs
+++ b/servant-client/src/Servant/Client.hs
@ -8,9 +8,8 @@
 {-# LANGUAGE TypeFamilies         #-}
 {-# LANGUAGE TypeOperators        #-}
 {-# LANGUAGE UndecidableInstances #-}
-#if !MIN_VERSION_base(4,8,0)
-{-# LANGUAGE OverlappingInstances #-}
-#endif
+
+#include "overlapping-compat.h"
 -- | This module provides 'client' which can automatically generate
 -- querying functions for each endpoint just from the type representing your
 -- API.
@ -123,19 +122,13 @@ instance (KnownSymbol capture, ToHttpApiData a, HasClient sublayout)
 -- side querying function that is created when calling 'client'
 -- will just require an argument that specifies the scheme, host
 -- and port to send the request to.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
  (MimeUnrender ct a, cts' ~ (ct ': cts)) => HasClient (Delete cts' a) where
  type Client (Delete cts' a) = ExceptT ServantError IO a
  clientWithRoute Proxy req baseurl manager =
    snd <$> performRequestCT (Proxy :: Proxy ct) H.methodDelete req baseurl manager

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  HasClient (Delete cts ()) where
  type Client (Delete cts ()) = ExceptT ServantError IO ()
  clientWithRoute Proxy req baseurl manager =
@ -143,10 +136,7 @@ instance

 -- | If you have a 'Delete xs (Headers ls x)' endpoint, the client expects the
 -- corresponding headers.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  ( MimeUnrender ct a, BuildHeadersTo ls, cts' ~ (ct ': cts)
  ) => HasClient (Delete cts' (Headers ls a)) where
  type Client (Delete cts' (Headers ls a)) = ExceptT ServantError IO (Headers ls a)
@ -160,19 +150,13 @@ instance
 -- side querying function that is created when calling 'client'
 -- will just require an argument that specifies the scheme, host
 -- and port to send the request to.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
  (MimeUnrender ct result) => HasClient (Get (ct ': cts) result) where
  type Client (Get (ct ': cts) result) = ExceptT ServantError IO result
  clientWithRoute Proxy req baseurl manager =
    snd <$> performRequestCT (Proxy :: Proxy ct) H.methodGet req baseurl manager

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  HasClient (Get (ct ': cts) ()) where
  type Client (Get (ct ': cts) ()) = ExceptT ServantError IO ()
  clientWithRoute Proxy req baseurl manager =
@ -180,10 +164,7 @@ instance

 -- | If you have a 'Get xs (Headers ls x)' endpoint, the client expects the
 -- corresponding headers.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  ( MimeUnrender ct a, BuildHeadersTo ls
  ) => HasClient (Get (ct ': cts) (Headers ls a)) where
  type Client (Get (ct ': cts) (Headers ls a)) = ExceptT ServantError IO (Headers ls a)
@ -240,19 +221,13 @@ instance (KnownSymbol sym, ToHttpApiData a, HasClient sublayout)
 -- side querying function that is created when calling 'client'
 -- will just require an argument that specifies the scheme, host
 -- and port to send the request to.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
  (MimeUnrender ct a) => HasClient (Post (ct ': cts) a) where
  type Client (Post (ct ': cts) a) = ExceptT ServantError IO a
  clientWithRoute Proxy req baseurl manager =
    snd <$> performRequestCT (Proxy :: Proxy ct) H.methodPost req baseurl manager

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  HasClient (Post (ct ': cts) ()) where
  type Client (Post (ct ': cts) ()) = ExceptT ServantError IO ()
  clientWithRoute Proxy req baseurl manager =
@ -260,10 +235,7 @@ instance

 -- | If you have a 'Post xs (Headers ls x)' endpoint, the client expects the
 -- corresponding headers.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  ( MimeUnrender ct a, BuildHeadersTo ls
  ) => HasClient (Post (ct ': cts) (Headers ls a)) where
  type Client (Post (ct ': cts) (Headers ls a)) = ExceptT ServantError IO (Headers ls a)
@ -277,19 +249,13 @@ instance
 -- side querying function that is created when calling 'client'
 -- will just require an argument that specifies the scheme, host
 -- and port to send the request to.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
  (MimeUnrender ct a) => HasClient (Put (ct ': cts) a) where
  type Client (Put (ct ': cts) a) = ExceptT ServantError IO a
  clientWithRoute Proxy req baseurl manager =
    snd <$> performRequestCT (Proxy :: Proxy ct) H.methodPut req baseurl manager

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  HasClient (Put (ct ': cts) ()) where
  type Client (Put (ct ': cts) ()) = ExceptT ServantError IO ()
  clientWithRoute Proxy req baseurl manager =
@ -297,10 +263,7 @@ instance

 -- | If you have a 'Put xs (Headers ls x)' endpoint, the client expects the
 -- corresponding headers.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  ( MimeUnrender ct a, BuildHeadersTo ls
  ) => HasClient (Put (ct ': cts) (Headers ls a)) where
  type Client (Put (ct ': cts) (Headers ls a)) = ExceptT ServantError IO (Headers ls a)
@ -314,19 +277,13 @@ instance
 -- side querying function that is created when calling 'client'
 -- will just require an argument that specifies the scheme, host
 -- and port to send the request to.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
  (MimeUnrender ct a) => HasClient (Patch (ct ': cts) a) where
  type Client (Patch (ct ': cts) a) = ExceptT ServantError IO a
  clientWithRoute Proxy req baseurl manager =
    snd <$> performRequestCT (Proxy :: Proxy ct) H.methodPatch req baseurl manager

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  HasClient (Patch (ct ': cts) ()) where
  type Client (Patch (ct ': cts) ()) = ExceptT ServantError IO ()
  clientWithRoute Proxy req baseurl manager =
@ -334,10 +291,7 @@ instance

 -- | If you have a 'Patch xs (Headers ls x)' endpoint, the client expects the
 -- corresponding headers.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  ( MimeUnrender ct a, BuildHeadersTo ls
  ) => HasClient (Patch (ct ': cts) (Headers ls a)) where
  type Client (Patch (ct ': cts) (Headers ls a)) = ExceptT ServantError IO (Headers ls a)
--- a/servant-client/test/Servant/ClientSpec.hs
+++ b/servant-client/test/Servant/ClientSpec.hs
@ -6,9 +6,6 @@
 {-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE GADTs                  #-}
 {-# LANGUAGE MultiParamTypeClasses  #-}
-#if !MIN_VERSION_base(4,8,0)
-{-# LANGUAGE OverlappingInstances   #-}
-#endif
 {-# LANGUAGE OverloadedStrings      #-}
 {-# LANGUAGE PolyKinds              #-}
 {-# LANGUAGE RecordWildCards        #-}
@ -20,6 +17,7 @@
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 {-# OPTIONS_GHC -fno-warn-name-shadowing #-}

+#include "overlapping-compat.h"
 module Servant.ClientSpec where

 #if !MIN_VERSION_base(4,8,0)
@ -323,33 +321,21 @@ pathGen = fmap NonEmpty path
 class GetNth (n :: Nat) a b | n a -> b where
    getNth :: Proxy n -> a -> b

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  GetNth 0 (x :<|> y) x where
      getNth _ (x :<|> _) = x

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  (GetNth (n - 1) x y) => GetNth n (a :<|> x) y where
      getNth _ (_ :<|> x) = getNth (Proxy :: Proxy (n - 1)) x

 class GetLast a b | a -> b where
    getLast :: a -> b

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  (GetLast b c) => GetLast (a :<|> b) c where
      getLast (_ :<|> b) = getLast b

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
  GetLast a a where
      getLast a = a
--- a/servant-docs/include/overlapping-compat.h
+++ b/servant-docs/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-docs/servant-docs.cabal
+++ b/servant-docs/servant-docs.cabal
@ -49,6 +49,7 @@ library
  hs-source-dirs: src
  default-language: Haskell2010
  ghc-options: -Wall
+  include-dirs: include

 executable greet-docs
  main-is: greet.hs
--- a/servant-docs/src/Servant/Docs/Internal.hs
+++ b/servant-docs/src/Servant/Docs/Internal.hs
@ -16,9 +16,8 @@
 {-# LANGUAGE TypeFamilies           #-}
 {-# LANGUAGE TypeOperators          #-}
 {-# LANGUAGE UndecidableInstances   #-}
-#if !MIN_VERSION_base(4,8,0)
-{-# LANGUAGE OverlappingInstances   #-}
-#endif
+
+#include "overlapping-compat.h"
 module Servant.Docs.Internal where

 import           Control.Applicative
@ -661,10 +660,7 @@ markdown api = unlines $

 -- | The generated docs for @a ':<|>' b@ just appends the docs
 --   for @a@ with the docs for @b@.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
         (HasDocs layout1, HasDocs layout2)
      => HasDocs (layout1 :<|> layout2) where

@ -692,10 +688,7 @@ instance (KnownSymbol sym, ToCapture (Capture sym a), HasDocs sublayout)
          symP = Proxy :: Proxy sym


-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLe #-}
-#endif
+instance OVERLAPPABLE_
        (ToSample a, IsNonEmpty cts, AllMimeRender cts a)
    => HasDocs (Delete cts a) where
  docsFor Proxy (endpoint, action) DocOptions{..} =
@ -707,10 +700,7 @@ instance
          t = Proxy :: Proxy cts
          p = Proxy :: Proxy a

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
        (ToSample a, IsNonEmpty cts, AllMimeRender cts a
         , AllHeaderSamples ls , GetHeaders (HList ls) )
    => HasDocs (Delete cts (Headers ls a)) where
@ -725,10 +715,7 @@ instance
          t = Proxy :: Proxy cts
          p = Proxy :: Proxy a

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLe #-}
-#endif
+instance OVERLAPPABLE_
        (ToSample a, IsNonEmpty cts, AllMimeRender cts a)
    => HasDocs (Get cts a) where
  docsFor Proxy (endpoint, action) DocOptions{..} =
@ -740,10 +727,7 @@ instance
          t = Proxy :: Proxy cts
          p = Proxy :: Proxy a

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
        (ToSample a, IsNonEmpty cts, AllMimeRender cts a
         , AllHeaderSamples ls , GetHeaders (HList ls) )
    => HasDocs (Get cts (Headers ls a)) where
@ -767,10 +751,7 @@ instance (KnownSymbol sym, HasDocs sublayout)
          action' = over headers (|> headername) action
          headername = pack $ symbolVal (Proxy :: Proxy sym)

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
        (ToSample a, IsNonEmpty cts, AllMimeRender cts a)
    => HasDocs (Post cts a) where
  docsFor Proxy (endpoint, action) DocOptions{..} =
@ -783,10 +764,7 @@ instance
          t = Proxy :: Proxy cts
          p = Proxy :: Proxy a

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         (ToSample a, IsNonEmpty cts, AllMimeRender cts a
         , AllHeaderSamples ls , GetHeaders (HList ls) )
    => HasDocs (Post cts (Headers ls a)) where
@ -802,10 +780,7 @@ instance
          t = Proxy :: Proxy cts
          p = Proxy :: Proxy a

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
        (ToSample a, IsNonEmpty cts, AllMimeRender cts a)
    => HasDocs (Put cts a) where
  docsFor Proxy (endpoint, action) DocOptions{..} =
@ -818,10 +793,7 @@ instance
          t = Proxy :: Proxy cts
          p = Proxy :: Proxy a

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
        ( ToSample a, IsNonEmpty cts, AllMimeRender cts a,
          AllHeaderSamples ls , GetHeaders (HList ls) )
    => HasDocs (Put cts (Headers ls a)) where
--- a/servant-examples/include/overlapping-compat.h
+++ b/servant-examples/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-foreign/include/overlapping-compat.h
+++ b/servant-foreign/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-foreign/servant-foreign.cabal
+++ b/servant-foreign/servant-foreign.cabal
@ -33,6 +33,7 @@ library
  hs-source-dirs:      src
  default-language:    Haskell2010
  ghc-options:         -Wall
+  include-dirs: include


 test-suite spec
--- a/servant-jquery/include/overlapping-compat.h
+++ b/servant-jquery/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-js/include/overlapping-compat.h
+++ b/servant-js/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-js/servant-js.cabal
+++ b/servant-js/servant-js.cabal
@ -49,6 +49,7 @@ library
  hs-source-dirs:      src
  default-language:    Haskell2010
  ghc-options:         -Wall
+  include-dirs: include

 executable counter
  main-is: counter.hs
--- a/servant-lucid/include/overlapping-compat.h
+++ b/servant-lucid/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-lucid/servant-lucid.cabal
+++ b/servant-lucid/servant-lucid.cabal
@ -30,3 +30,4 @@ library
                     , servant == 0.5.*
  hs-source-dirs:      src
  default-language:    Haskell2010
+  include-dirs: include
--- a/servant-lucid/src/Servant/HTML/Lucid.hs
+++ b/servant-lucid/src/Servant/HTML/Lucid.hs
@ -3,9 +3,8 @@
 {-# LANGUAGE FlexibleInstances     #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE OverloadedStrings     #-}
-#if !MIN_VERSION_base(4,8,0)
-{-# LANGUAGE OverlappingInstances  #-}
-#endif
+
+#include "overlapping-compat.h"

 -- | An @HTML@ empty data type with `MimeRender` instances for @lucid@'s
 -- `ToHtml` class and `Html` datatype.
@ -28,16 +27,10 @@ data HTML deriving Typeable
 instance Accept HTML where
    contentType _ = "text" M.// "html" M./: ("charset", "utf-8")

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
         ToHtml a => MimeRender HTML a where
    mimeRender _ = renderBS . toHtml

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         MimeRender HTML (Html a) where
    mimeRender _ = renderBS
--- a/servant-mock/include/overlapping-compat.h
+++ b/servant-mock/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-mock/servant-mock.cabal
+++ b/servant-mock/servant-mock.cabal
@ -34,6 +34,7 @@ library
    wai >= 3.0 && <3.3
  hs-source-dirs:      src
  default-language:    Haskell2010
+  include-dirs: include

 executable mock-app
  main-is: main.hs
--- a/servant-property/include/overlapping-compat.h
+++ b/servant-property/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-server/include/overlapping-compat.h
+++ b/servant-server/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant-server/servant-server.cabal
+++ b/servant-server/servant-server.cabal
@ -69,6 +69,7 @@ library
  hs-source-dirs: src
  default-language: Haskell2010
  ghc-options: -Wall
+  include-dirs: include

 executable greet
  main-is: greet.hs
@ -134,3 +135,4 @@ test-suite doctests
 buildable: True
 default-language: Haskell2010
 ghc-options: -threaded
+ include-dirs: include
--- a/servant-server/src/Servant/Server/Internal.hs
+++ b/servant-server/src/Servant/Server/Internal.hs
@ -8,9 +8,8 @@
 {-# LANGUAGE ScopedTypeVariables        #-}
 {-# LANGUAGE TypeFamilies               #-}
 {-# LANGUAGE TypeOperators              #-}
-#if !MIN_VERSION_base(4,8,0)
-{-# LANGUAGE OverlappingInstances       #-}
-#endif
+
+#include "overlapping-compat.h"

 module Servant.Server.Internal
  ( module Servant.Server.Internal
@ -206,10 +205,7 @@ methodRouterEmpty method action = LeafRouter route'
 -- to be returned. You can use 'Control.Monad.Trans.Except.throwE' to
 -- painlessly error out if the conditions for a successful deletion
 -- are not met.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
         ( AllCTRender ctypes a
         ) => HasServer (Delete ctypes a) where

@ -217,10 +213,7 @@ instance

  route Proxy = methodRouter methodDelete (Proxy :: Proxy ctypes) ok200

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         HasServer (Delete ctypes ()) where

  type ServerT (Delete ctypes ()) m = m ()
@ -228,10 +221,7 @@ instance
  route Proxy = methodRouterEmpty methodDelete

 -- Add response headers
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         ( GetHeaders (Headers h v), AllCTRender ctypes v
         ) => HasServer (Delete ctypes (Headers h v)) where

@ -252,10 +242,7 @@ instance
 -- (returning a status code of 200). If there was no @Accept@ header or it
 -- was @*\/\*@, we return encode using the first @Content-Type@ type on the
 -- list.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
         ( AllCTRender ctypes a ) => HasServer (Get ctypes a) where

  type ServerT (Get ctypes a) m = m a
@ -263,10 +250,7 @@ instance
  route Proxy = methodRouter methodGet (Proxy :: Proxy ctypes) ok200

 -- '()' ==> 204 No Content
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
          HasServer (Get ctypes ()) where

  type ServerT (Get ctypes ()) m = m ()
@ -274,10 +258,7 @@ instance
  route Proxy = methodRouterEmpty methodGet

 -- Add response headers
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
          ( GetHeaders (Headers h v), AllCTRender ctypes v
          ) => HasServer (Get ctypes (Headers h v)) where

@ -329,10 +310,7 @@ instance (KnownSymbol sym, FromHttpApiData a, HasServer sublayout)
 -- (returning a status code of 201). If there was no @Accept@ header or it
 -- was @*\/\*@, we return encode using the first @Content-Type@ type on the
 -- list.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
         ( AllCTRender ctypes a
         ) => HasServer (Post ctypes a) where

@ -340,10 +318,7 @@ instance

  route Proxy = methodRouter methodPost (Proxy :: Proxy ctypes) created201

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         HasServer (Post ctypes ()) where

  type ServerT (Post ctypes ()) m = m ()
@ -351,10 +326,7 @@ instance
  route Proxy = methodRouterEmpty methodPost

 -- Add response headers
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         ( GetHeaders (Headers h v), AllCTRender ctypes v
         ) => HasServer (Post ctypes (Headers h v)) where

@ -375,20 +347,14 @@ instance
 -- (returning a status code of 200). If there was no @Accept@ header or it
 -- was @*\/\*@, we return encode using the first @Content-Type@ type on the
 -- list.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
         ( AllCTRender ctypes a) => HasServer (Put ctypes a) where

  type ServerT (Put ctypes a) m = m a

  route Proxy = methodRouter methodPut (Proxy :: Proxy ctypes) ok200

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         HasServer (Put ctypes ()) where

  type ServerT (Put ctypes ()) m = m ()
@ -396,10 +362,7 @@ instance
  route Proxy = methodRouterEmpty methodPut

 -- Add response headers
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         ( GetHeaders (Headers h v), AllCTRender ctypes v
         ) => HasServer (Put ctypes (Headers h v)) where

@ -418,20 +381,14 @@ instance
 -- If successfully returning a value, we just require that its type has
 -- a 'ToJSON' instance and servant takes care of encoding it for you,
 -- yielding status code 200 along the way.
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
+instance OVERLAPPABLE_
         ( AllCTRender ctypes a) => HasServer (Patch ctypes a) where

  type ServerT (Patch ctypes a) m = m a

  route Proxy = methodRouter methodPatch (Proxy :: Proxy ctypes) ok200

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
          HasServer (Patch ctypes ()) where

  type ServerT (Patch ctypes ()) m = m ()
@ -439,10 +396,7 @@ instance
  route Proxy = methodRouterEmpty methodPatch

 -- Add response headers
-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
+instance OVERLAPPING_
         ( GetHeaders (Headers h v), AllCTRender ctypes v
         ) => HasServer (Patch ctypes (Headers h v)) where

--- a/servant-server/test/Doctests.hs
+++ b/servant-server/test/Doctests.hs
@ -10,7 +10,7 @@ main :: IO ()
 main = do
    files <- find always (extension ==? ".hs") "src"
    mCabalMacrosFile <- getCabalMacrosFile
-    doctest $ "-isrc" :
+    doctest $ "-isrc" : "-Iinclude" :
              (maybe [] (\ f -> ["-optP-include", "-optP" ++ f]) mCabalMacrosFile) ++
              "-XOverloadedStrings" :
              "-XFlexibleInstances" :
--- a/servant-session/include/overlapping-compat.h
+++ b/servant-session/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant/include/overlapping-compat.h
+++ b/servant/include/overlapping-compat.h
@ -0,0 +1,8 @@
+#if __GLASGOW_HASKELL__ >= 710
+#define OVERLAPPABLE_ {-# OVERLAPPABLE #-}
+#define OVERLAPPING_  {-# OVERLAPPING #-}
+#else
+{-# LANGUAGE OverlappingInstances #-}
+#define OVERLAPPABLE_
+#define OVERLAPPING_
+#endif
--- a/servant/servant.cabal
+++ b/servant/servant.cabal
@ -81,6 +81,7 @@ library
                  , TypeSynonymInstances
                  , UndecidableInstances
  ghc-options: -Wall
+  include-dirs: include

 test-suite spec
  type: exitcode-stdio-1.0
@ -118,3 +119,4 @@ test-suite doctests
 buildable: True
 default-language: Haskell2010
 ghc-options: -threaded
+ include-dirs: include
--- a/servant/src/Servant/API/ResponseHeaders.hs
+++ b/servant/src/Servant/API/ResponseHeaders.hs
@ -12,11 +12,9 @@
 {-# LANGUAGE TypeFamilies           #-}
 {-# LANGUAGE TypeOperators          #-}
 {-# LANGUAGE UndecidableInstances   #-}
-#if !MIN_VERSION_base(4,8,0)
-{-# LANGUAGE OverlappingInstances   #-}
-#endif
 {-# OPTIONS_HADDOCK not-home        #-}

+#include "overlapping-compat.h"
 -- | This module provides facilities for adding headers to a response.
 --
 -- >>> let headerVal = addHeader "some-url" 5 :: Headers '[Header "Location" String] Int
@ -68,19 +66,12 @@ class BuildHeadersTo hs where
    -- the values are interspersed with commas before deserialization (see
    -- <http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 RFC2616 Sec 4.2>)

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
-         BuildHeadersTo '[] where
+instance OVERLAPPING_ BuildHeadersTo '[] where
    buildHeadersTo _ = HNil

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
-         ( FromByteString v, BuildHeadersTo xs, KnownSymbol h, Contains h xs ~ 'False
-         ) => BuildHeadersTo ((Header h v) ': xs) where
+instance OVERLAPPABLE_ ( FromByteString v, BuildHeadersTo xs, KnownSymbol h
+                       , Contains h xs ~ 'False)
+         => BuildHeadersTo ((Header h v) ': xs) where
    buildHeadersTo headers =
      let wantedHeader = CI.mk . pack $ symbolVal (Proxy :: Proxy h)
          matching = snd <$> filter (\(h, _) -> h == wantedHeader) headers
@ -96,38 +87,22 @@ instance
 class GetHeaders ls where
    getHeaders :: ls -> [HTTP.Header]

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
-         GetHeaders (HList '[]) where
+instance OVERLAPPING_ GetHeaders (HList '[]) where
    getHeaders _ = []

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
-         ( KnownSymbol h, ToByteString x, GetHeaders (HList xs)
-         ) => GetHeaders (HList (Header h x ': xs)) where
+instance OVERLAPPABLE_ ( KnownSymbol h, ToByteString x, GetHeaders (HList xs))
+         => GetHeaders (HList (Header h x ': xs)) where
    getHeaders hdrs = case hdrs of
        Header val `HCons` rest -> (headerName , toByteString' val):getHeaders rest
        UndecodableHeader h `HCons` rest -> (headerName,  h) : getHeaders rest
        MissingHeader `HCons` rest -> getHeaders rest
      where headerName = CI.mk . pack $ symbolVal (Proxy :: Proxy h)

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
-         GetHeaders (Headers '[] a) where
+instance OVERLAPPING_ GetHeaders (Headers '[] a) where
    getHeaders _ = []

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
-         ( KnownSymbol h, GetHeaders (HList rest), ToByteString v
-         ) => GetHeaders (Headers (Header h v ': rest) a) where
+instance OVERLAPPABLE_ ( KnownSymbol h, GetHeaders (HList rest), ToByteString v)
+         => GetHeaders (Headers (Header h v ': rest) a) where
    getHeaders hs = getHeaders $ getHeadersHList hs

 -- * Adding
@ -138,21 +113,13 @@ class AddHeader h v orig new
  addHeader :: v -> orig -> new  -- ^ N.B.: The same header can't be added multiple times


-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPING #-}
-#endif
-         ( KnownSymbol h, ToByteString v, Contains h (fst ': rest) ~ 'False
-         ) => AddHeader h v (Headers (fst ': rest)  a) (Headers (Header h v  ': fst ': rest) a) where
+instance OVERLAPPING_ ( KnownSymbol h, ToByteString v, Contains h (fst ': rest) ~ 'False)
+         => AddHeader h v (Headers (fst ': rest)  a) (Headers (Header h v  ': fst ': rest) a) where
    addHeader a (Headers resp heads) = Headers resp (HCons (Header a) heads)

-instance
-#if MIN_VERSION_base(4,8,0)
-         {-# OVERLAPPABLE #-}
-#endif
-         ( KnownSymbol h, ToByteString v
-         , new ~ (Headers '[Header h v] a)
-         ) => AddHeader h v a new where
+instance OVERLAPPABLE_ ( KnownSymbol h, ToByteString v
+                       , new ~ (Headers '[Header h v] a))
+         => AddHeader h v a new where
    addHeader a resp = Headers resp (HCons (Header a) HNil)

 type family Contains x xs where
--- a/servant/test/Doctests.hs
+++ b/servant/test/Doctests.hs
@ -11,7 +11,7 @@ main = do
    files <- find always (extension ==? ".hs") "src"
    tfiles <- find always (extension ==? ".hs") "test/Servant"
    mCabalMacrosFile <- getCabalMacrosFile
-    doctest $ "-isrc" :
+    doctest $ "-isrc" : "-Iinclude" :
              (maybe [] (\ f -> ["-optP-include", "-optP" ++ f]) mCabalMacrosFile) ++
              "-XOverloadedStrings" :
              "-XFlexibleInstances" :