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+-- Desugarer outputs of this program when compiled with and without -XStrict
+-- should be the same because this program has only one binder (`a` in function
+-- `primitive`), but the binder is annotated with a laziness annotation, so
+-- -XStrict should have no effect on that binder.
+--
+-- Derived methods are also effected by -XStrict, but in our case we derive via
+-- GND which just generates coercions like
+--
+--     instance Functor m => Functor (StateT s m) where
+--       fmap
+--         = coerce
+--             @(forall (a_aJ2 :: TYPE LiftedRep) (b_aJ3 :: TYPE LiftedRep).
+--               a_aJ2 -> b_aJ3
+--               -> StateT s_aDW m_aDX a_aJ2 -> StateT s_aDW m_aDX b_aJ3)
+--             @(forall (a_aJ2 :: TYPE LiftedRep) (b_aJ3 :: TYPE LiftedRep).
+--               a_aJ2 -> b_aJ3
+--               -> StateT s_aDW m_aDX a_aJ2 -> StateT s_aDW m_aDX b_aJ3)
+--             fmap
+--
+-- So really -XStrict shouldn't have any effect on this program.
+
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE MagicHash                  #-}
+{-# LANGUAGE MultiParamTypeClasses      #-}
+{-# LANGUAGE TypeFamilies               #-}
+{-# LANGUAGE UnboxedTuples              #-}
+
+module K where
+
+import qualified Control.Monad.State.Strict as S
+import Control.Monad.Trans
+import GHC.Exts
+
+class Monad m => PrimMonad m where
+  type PrimState m
+  primitive :: (State# (PrimState m) -> (# State# (PrimState m), a #)) -> m a
+
+newtype StateT s m a = StateT (S.StateT s m a)
+  deriving (Functor, Applicative, Monad, MonadTrans)
+
+instance PrimMonad m => PrimMonad (StateT s m) where
+  type PrimState (StateT s m) = PrimState m
+  primitive ~a = lift (primitive a) ; {-# INLINE primitive #-}