diff --git a/yesod-core/src/Yesod/Core/Class/Yesod.hs b/yesod-core/src/Yesod/Core/Class/Yesod.hs
index 85a9d10c..2a2c1b04 100644
--- a/yesod-core/src/Yesod/Core/Class/Yesod.hs
+++ b/yesod-core/src/Yesod/Core/Class/Yesod.hs
@@ -531,8 +531,8 @@ widgetToPageContent :: Yesod site
                     => WidgetFor site ()
                     -> HandlerFor site (PageContent (Route site))
 widgetToPageContent w = do
-  jsAttrs <- jsAttributesHandler
-  HandlerFor $ \hd -> do
+ jsAttrs <- jsAttributesHandler
+ HandlerFor $ \hd -> do
   master <- unHandlerFor getYesod hd
   ref <- newIORef mempty
   unWidgetFor w WidgetData
diff --git a/yesod-core/src/Yesod/Core/Handler.hs b/yesod-core/src/Yesod/Core/Handler.hs
index 57c814ba..b8f82419 100644
--- a/yesod-core/src/Yesod/Core/Handler.hs
+++ b/yesod-core/src/Yesod/Core/Handler.hs
@@ -9,6 +9,7 @@
 {-# LANGUAGE TypeFamilies               #-}
 {-# LANGUAGE RankNTypes                 #-}
 {-# LANGUAGE ScopedTypeVariables        #-}
+{-# LANGUAGE TemplateHaskell            #-}
 ---------------------------------------------------------
 --
 -- Module        : Yesod.Handler
diff --git a/yesod-core/yesod-core.cabal b/yesod-core/yesod-core.cabal
index e3700fb9..e63819a4 100644
--- a/yesod-core/yesod-core.cabal
+++ b/yesod-core/yesod-core.cabal
@@ -8,7 +8,7 @@ synopsis:        Creation of type-safe, RESTful web applications.
 description:     API docs and the README are available at <http://www.stackage.org/package/yesod-core>
 category:        Web, Yesod
 stability:       Stable
-cabal-version:   >= 1.8
+cabal-version:   >= 1.10
 build-type:      Simple
 homepage:        http://www.yesodweb.com/
 extra-source-files:
@@ -22,6 +22,7 @@ extra-source-files:
   README.md
 
 library
+    default-language: Haskell2010
     hs-source-dirs: src
 
     build-depends:   base                  >= 4.10     && < 5
@@ -97,14 +98,12 @@ library
                      Yesod.Routes.TH.RouteAttrs
 
     ghc-options:     -Wall
-    -- Following line added due to: https://github.com/yesodweb/yesod/issues/545
-    -- This looks like a GHC bug
-    extensions:      MultiParamTypeClasses
 
     -- Workaround for: http://ghc.haskell.org/trac/ghc/ticket/8443
-    extensions:      TemplateHaskell
+    other-extensions:      TemplateHaskell
 
 test-suite test-routes
+    default-language: Haskell2010
     type: exitcode-stdio-1.0
     main-is: RouteSpec.hs
     hs-source-dirs: test, src
@@ -121,7 +120,7 @@ test-suite test-routes
                    Yesod.Routes.TH.Types
 
     -- Workaround for: http://ghc.haskell.org/trac/ghc/ticket/8443
-    extensions:      TemplateHaskell
+    other-extensions:      TemplateHaskell
 
     build-depends: base
                  , hspec
@@ -134,6 +133,7 @@ test-suite test-routes
                  , HUnit
 
 test-suite tests
+    default-language: Haskell2010
     type: exitcode-stdio-1.0
     main-is: test.hs
     hs-source-dirs: test
@@ -201,9 +201,10 @@ test-suite tests
                   , warp
                   , yesod-core
     ghc-options:     -Wall -threaded
-    extensions: TemplateHaskell
+    other-extensions: TemplateHaskell
 
 benchmark widgets
+    default-language: Haskell2010
     type: exitcode-stdio-1.0
     hs-source-dirs: bench
     build-depends:  base