Include the request that failed in FailureResponse.

servant-client/src/Servant/Common/Req.hs

@@ -48,7 +48,8 @@ import Web.HttpApiData
 
 data ServantError
   = FailureResponse
-    { responseStatus            :: Status
+    { failingRequest            :: Request
+    , responseStatus            :: Status
     , responseContentType       :: MediaType
     , responseBody              :: ByteString
     }
@@ -71,8 +72,8 @@ data ServantError
   deriving (Show, Typeable)
 
 instance Eq ServantError where
-  FailureResponse a b c == FailureResponse x y z =
-    (a, b, c) == (x, y, z)
+  FailureResponse a b c d == FailureResponse w x y z =
+    (show a, b, c, d) == (show w, x, y, z)
   DecodeFailure a b c == DecodeFailure x y z =
     (a, b, c) == (x, y, z)
   UnsupportedContentType a b == UnsupportedContentType x y =
@@ -250,7 +251,7 @@ performRequest reqMethod req = do
                    Nothing -> throwError $ InvalidContentTypeHeader (cs t) body
                    Just t' -> pure t'
       unless (status_code >= 200 && status_code < 300) $
-        throwError $ FailureResponse status ct body
+        throwError $ FailureResponse request status ct body
       return (status_code, body, ct, hdrs, response)
 
 performRequestCT :: MimeUnrender ct result => Proxy ct -> Method -> Req

servant-client/test/Servant/ClientSpec.hs

@@ -372,7 +372,7 @@ failSpec = beforeAll (startWaiApp failServer) $ afterAll endWaiApp $ do
         let (_ :<|> getDeleteEmpty :<|> _) = client api
         Left res <- runClientM getDeleteEmpty (ClientEnv manager baseUrl)
         case res of
-          FailureResponse (HTTP.Status 404 "Not Found") _ _ -> return ()
+          FailureResponse _ (HTTP.Status 404 "Not Found") _ _ -> return ()
           _ -> fail $ "expected 404 response, but got " <> show res
 
       it "reports DecodeFailure" $ \(_, baseUrl) -> do