diff --git a/src/Servant/Client.hs b/src/Servant/Client.hs
index 2c619f0d..c50b5471 100644
--- a/src/Servant/Client.hs
+++ b/src/Servant/Client.hs
@@ -13,6 +13,7 @@
 module Servant.Client
   ( client
   , HasClient(..)
+  , Client
   , ServantError(..)
   , module Servant.Common.BaseUrl
   ) where
@@ -130,7 +131,7 @@ instance (MimeUnrender ct result) => HasClient (Get (ct ': cts) result) where
 -- | If you have a 'Get xs ()' endpoint, the client expects a 204 No Content
 -- HTTP header.
 instance HasClient (Get (ct ': cts) ()) where
-  type Client (Get (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
+  type Client' (Get (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
   clientWithRoute Proxy req host =
     performRequestNoBody H.methodGet req [204] host
 
@@ -167,7 +168,7 @@ instance (KnownSymbol sym, ToText a, HasClient sublayout)
 
   clientWithRoute Proxy req mval =
     clientWithRoute (Proxy :: Proxy sublayout) $
-      maybe req (\value -> addHeader hname value req) mval
+      maybe req (\value -> Servant.Common.Req.addHeader hname value req) mval
 
     where hname = symbolVal (Proxy :: Proxy sym)
 
@@ -184,7 +185,7 @@ instance (MimeUnrender ct a) => HasClient (Post (ct ': cts) a) where
 -- | If you have a 'Post xs ()' endpoint, the client expects a 204 No Content
 -- HTTP header.
 instance HasClient (Post (ct ': cts) ()) where
-  type Client (Post (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
+  type Client' (Post (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
   clientWithRoute Proxy req host =
     void $ performRequestNoBody H.methodPost req [204] host
 
@@ -201,7 +202,7 @@ instance (MimeUnrender ct a) => HasClient (Put (ct ': cts) a) where
 -- | If you have a 'Put xs ()' endpoint, the client expects a 204 No Content
 -- HTTP header.
 instance HasClient (Put (ct ': cts) ()) where
-  type Client (Put (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
+  type Client' (Put (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
   clientWithRoute Proxy req host =
     void $ performRequestNoBody H.methodPut req [204] host
 
@@ -210,7 +211,7 @@ instance HasClient (Put (ct ': cts) ()) where
 -- will just require an argument that specifies the scheme, host
 -- and port to send the request to.
 instance (MimeUnrender ct a) => HasClient (Patch (ct ': cts) a) where
-  type Client (Patch (ct ': cts) a) = BaseUrl -> EitherT ServantError IO a
+  type Client' (Patch (ct ': cts) a) = BaseUrl -> EitherT ServantError IO a
 
   clientWithRoute Proxy req host =
     performRequestCT (Proxy :: Proxy ct) H.methodPatch req [200,201] host
@@ -218,7 +219,7 @@ instance (MimeUnrender ct a) => HasClient (Patch (ct ': cts) a) where
 -- | If you have a 'Patch xs ()' endpoint, the client expects a 204 No Content
 -- HTTP header.
 instance HasClient (Patch (ct ': cts) ()) where
-  type Client (Patch (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
+  type Client' (Patch (ct ': cts) ()) = BaseUrl -> EitherT ServantError IO ()
   clientWithRoute Proxy req host =
     void $ performRequestNoBody H.methodPatch req [204] host
 
@@ -489,7 +490,7 @@ instance (MimeRender ct a, HasClient sublayout)
   clientWithRoute Proxy req body =
     clientWithRoute (Proxy :: Proxy sublayout) $ do
       let ctProxy = Proxy :: Proxy ct
-      setRQBody (toByteString ctProxy body) (contentType ctProxy) req
+      setRQBody (mimeRender ctProxy body) (contentType ctProxy) req
 
 -- | Make the querying function append @path@ to the request path.
 instance (KnownSymbol path, HasClient sublayout) => HasClient (path :> sublayout) where
diff --git a/src/Servant/Common/Req.hs b/src/Servant/Common/Req.hs
index a0ffbc14..60c53eb8 100644
--- a/src/Servant/Common/Req.hs
+++ b/src/Servant/Common/Req.hs
@@ -172,7 +172,7 @@ performRequestCT ct reqMethod req wantedStatus reqHost = do
   either
     (left . (\s -> DecodeFailure s respCT respBody))
     return
-    (fromByteString ct respBody)
+    (mimeUnrender ct respBody)
 
 performRequestNoBody :: Method -> Req -> [Int] -> BaseUrl -> EitherT ServantError IO ()
 performRequestNoBody reqMethod req wantedStatus reqHost = do
diff --git a/test/Servant/ClientSpec.hs b/test/Servant/ClientSpec.hs
index 7b1645c0..ff043ab1 100644
--- a/test/Servant/ClientSpec.hs
+++ b/test/Servant/ClientSpec.hs
@@ -1,42 +1,42 @@
-{-# LANGUAGE GADTs #-}
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE ViewPatterns #-}
-{-# LANGUAGE DeriveGeneric #-}
-{-# LANGUAGE TypeOperators #-}
-{-# LANGUAGE RecordWildCards #-}
-{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE DataKinds          #-}
+{-# LANGUAGE DeriveGeneric      #-}
+{-# LANGUAGE FlexibleContexts   #-}
+{-# LANGUAGE GADTs              #-}
+{-# LANGUAGE OverloadedStrings  #-}
+{-# LANGUAGE RecordWildCards    #-}
 {-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE TypeOperators      #-}
 {-# OPTIONS_GHC -fcontext-stack=25 #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 module Servant.ClientSpec where
 
-import Control.Applicative
-import qualified Control.Arrow as Arrow
-import Control.Concurrent
-import Control.Exception
-import Control.Monad.Trans.Either
-import Data.Aeson
-import Data.ByteString.Lazy (ByteString)
-import Data.Char
-import Data.Foldable (forM_)
-import Data.Monoid
-import Data.Proxy
-import qualified Data.Text as T
-import GHC.Generics
-import qualified Network.HTTP.Client as C
-import Network.HTTP.Media
-import Network.HTTP.Types
-import Network.Socket
-import Network.Wai hiding (Response)
-import Network.Wai.Handler.Warp
-import Test.Hspec
-import Test.Hspec.QuickCheck
-import Test.HUnit
-import Test.QuickCheck
+import           Control.Applicative
+import qualified Control.Arrow              as Arrow
+import           Control.Concurrent
+import           Control.Exception
+import           Control.Monad.Trans.Either
+import           Data.Aeson
+import           Data.ByteString.Lazy       (ByteString)
+import           Data.Char
+import           Data.Foldable              (forM_)
+import           Data.Monoid
+import           Data.Proxy
+import qualified Data.Text                  as T
+import           GHC.Generics
+import qualified Network.HTTP.Client        as C
+import           Network.HTTP.Media
+import           Network.HTTP.Types
+import           Network.Socket
+import           Network.Wai                hiding (Response)
+import           Network.Wai.Handler.Warp
+import           Test.Hspec
+import           Test.Hspec.QuickCheck
+import           Test.HUnit
+import           Test.QuickCheck
 
-import Servant.API
-import Servant.Client
-import Servant.Server
+import           Servant.API
+import           Servant.Client
+import           Servant.Server
 
 -- * test data types
 
@@ -289,8 +289,8 @@ spec = do
         _ -> fail $ "expected InvalidContentTypeHeader, but got " <> show res
 
 data WrappedApi where
-  WrappedApi :: (HasServer api, Server api ~ EitherT (Int, String) IO a,
-                 HasClient api, Client api ~ (BaseUrl -> EitherT ServantError IO ())) =>
+  WrappedApi :: (HasServer (Canonicalize api), Server api ~ EitherT (Int, String) IO a,
+                 HasClient (Canonicalize api), Client api ~ (BaseUrl -> EitherT ServantError IO ())) =>
     Proxy api -> WrappedApi