@@ -98,6 +98,10 @@ import Web.FormUrlEncoded (FromForm, ToForm,
98import Prelude ()
98import Prelude ()
99import Prelude.Compat
99import Prelude.Compat
101+#if MIN_VERSION_base(4,9,0)
102+import qualified GHC.TypeLits as TL
101-- * Provided content types
105-- * Provided content types
102data JSON deriving Typeable
106data JSON deriving Typeable
103data PlainText deriving Typeable
107data PlainText deriving Typeable
@@ -180,6 +184,12 @@ instance OVERLAPPABLE_
180 amrs = allMimeRender pctyps val
184 amrs = allMimeRender pctyps val
181 lkup = fmap (\(a,b) -> (a, (fromStrict $ M.renderHeader a, b))) amrs
185 lkup = fmap (\(a,b) -> (a, (fromStrict $ M.renderHeader a, b))) amrs
187+#if MIN_VERSION_base(4,9,0)
188+instance TL.TypeError (TL.Text "No instance for (), use NoContent instead.")
189+ => AllCTRender '[] () where
190+ handleAcceptH _ _ _ = error "unreachable"
183--------------------------------------------------------------------------
193--------------------------------------------------------------------------
184-- * Unrender
194-- * Unrender