diff --git a/yesod-bin/Devel.hs b/yesod-bin/Devel.hs
index 7e52a68f..bb8d6c11 100644
--- a/yesod-bin/Devel.hs
+++ b/yesod-bin/Devel.hs
@@ -174,28 +174,28 @@ reverseProxy opts appPortVar = do
                 manager
         defaultSettings' = maybe id (setHost . fromString) (develHost opts) defaultSettings
         runProxyTls port app = do
-            let certDef = $(embedFile "certificate.pem")
-                keyDef = $(embedFile "key.pem")
-                certOpts = bisequence $ (certPath &&& keyPath) opts
-                theSettings = maybe (tlsSettingsMemory certDef keyDef) (uncurry tlsSettings) certOpts
-            runTLS theSettings (setPort port defaultSettings') $ \req send -> do
-                let req' = req
-                        { requestHeaders
-                            = ("X-Forwarded-Proto", "https")
-                            -- Workaround for
-                            -- https://github.com/yesodweb/wai/issues/478, where
-                            -- the Host headers aren't set. Without this, generated
-                            -- URLs from guestApproot are incorrect, see:
-                            -- https://github.com/yesodweb/yesod-scaffold/issues/114
-                            : (case lookup "host" (requestHeaders req) of
-                                Nothing ->
-                                    case requestHeaderHost req of
-                                        Just host -> (("Host", host):)
-                                        Nothing -> id
-                                Just _ -> id)
-                            (requestHeaders req)
-                        }
-                app req' send
+          let certDef = $(embedFile "certificate.pem")
+              keyDef = $(embedFile "key.pem")
+              certOpts = bisequence $ (certPath &&& keyPath) opts
+              theSettings = maybe (tlsSettingsMemory certDef keyDef) (uncurry tlsSettings) certOpts
+          runTLS theSettings (setPort port defaultSettings') $ \req send -> do
+            let req' = req
+                    { requestHeaders
+                        = ("X-Forwarded-Proto", "https")
+                        -- Workaround for
+                        -- https://github.com/yesodweb/wai/issues/478, where
+                        -- the Host headers aren't set. Without this, generated
+                        -- URLs from guestApproot are incorrect, see:
+                        -- https://github.com/yesodweb/yesod-scaffold/issues/114
+                        : (case lookup "host" (requestHeaders req) of
+                            Nothing ->
+                                case requestHeaderHost req of
+                                    Just host -> (("Host", host):)
+                                    Nothing -> id
+                            Just _ -> id)
+                          (requestHeaders req)
+                    }
+            app req' send
         httpProxy = runSettings (setPort (develPort opts) defaultSettings') proxyApp
         httpsProxy = runProxyTls (develTlsPort opts) proxyApp
     say "Application can be accessed at:\n"