diff --git a/modules/openapi-generator/src/main/resources/haskell-servant/API.mustache b/modules/openapi-generator/src/main/resources/haskell-servant/API.mustache
index 400dee38f1db..684c469d33e3 100644
--- a/modules/openapi-generator/src/main/resources/haskell-servant/API.mustache
+++ b/modules/openapi-generator/src/main/resources/haskell-servant/API.mustache
@@ -61,7 +61,7 @@ import           Servant.Client                     (ClientEnv, Scheme (Http), C
                                                      mkClientEnv, parseBaseUrl)
 import           Servant.Client.Core                (baseUrlPort, baseUrlHost)
 import           Servant.Client.Internal.HttpClient (ClientM (..))
-import           Servant.Server                     (Handler (..)){{#serveStatic}}
+import           Servant.Server                     (Handler (..), Application){{#serveStatic}}
 import           Servant.Server.StaticFiles         (serveDirectoryFileServer){{/serveStatic}}
 import           Web.FormUrlEncoded
 import           Web.HttpApiData
@@ -219,8 +219,8 @@ requestMiddlewareId a = a
 
 -- | Run the {{title}} server at the provided host and port.
 run{{title}}Server
-:: (MonadIO m, MonadThrow m)
-=> Config -> {{title}}Backend (ExceptT ServerError IO) -> m ()
+  :: (MonadIO m, MonadThrow m)
+  => Config -> {{title}}Backend (ExceptT ServerError IO) -> m ()
 run{{title}}Server config backend = run{{title}}MiddlewareServer config requestMiddlewareId backend
 
 -- | Run the {{title}} server at the provided host and port.
diff --git a/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/API.hs b/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/API.hs
index a6d82d949705..a70eb607c7aa 100644
--- a/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/API.hs
+++ b/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/API.hs
@@ -61,7 +61,7 @@ import           Servant.Client                     (ClientEnv, Scheme (Http), C
                                                      mkClientEnv, parseBaseUrl)
 import           Servant.Client.Core                (baseUrlPort, baseUrlHost)
 import           Servant.Client.Internal.HttpClient (ClientM (..))
-import           Servant.Server                     (Handler (..))
+import           Servant.Server                     (Handler (..), Application)
 import           Servant.Server.StaticFiles         (serveDirectoryFileServer)
 import           Web.FormUrlEncoded
 import           Web.HttpApiData
@@ -271,8 +271,8 @@ requestMiddlewareId a = a
 
 -- | Run the OpenAPIPetstore server at the provided host and port.
 runOpenAPIPetstoreServer
-:: (MonadIO m, MonadThrow m)
-=> Config -> OpenAPIPetstoreBackend (ExceptT ServerError IO) -> m ()
+  :: (MonadIO m, MonadThrow m)
+  => Config -> OpenAPIPetstoreBackend (ExceptT ServerError IO) -> m ()
 runOpenAPIPetstoreServer config backend = runOpenAPIPetstoreMiddlewareServer config requestMiddlewareId backend
 
 -- | Run the OpenAPIPetstore server at the provided host and port.