The use of ‘~’ without TypeOperators
will become an error in a future GHC release.
says new ghc
{-# LANGUAGE DataKinds, FlexibleInstances #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE TypeOperators #-}
#if MIN_VERSION_persistent_template(2,8,0)
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE StandaloneDeriving #-}
-}
{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE RankNTypes #-}