Doesn't compile on GHC 9.0.2

[pkozakowski]

I'm getting the following error trying to build on GHC 9.0.2:

monad-validate      > /tmp/zsh-1000/stack-769e9f00254e8aaf/monad-validate-1.2.0.0/src/Control/Monad/Validate/Internal.hs:299:41: error:                                                                            
monad-validate      >     • Couldn't match type: forall (s1 :: MonoMaybeS).                              
monad-validate      >                            StateT (MonoMaybe s1 e) (ExceptT e m) b
monad-validate      >                      with: StateT (MonoMaybe s e) (ExceptT e m) b
monad-validate      >       Expected: ValidateT e m b -> StateT (MonoMaybe s e) (ExceptT e m) b       
monad-validate      >         Actual: ValidateT e m b                    
monad-validate      >                 -> forall (s :: MonoMaybeS). StateT (MonoMaybe s e) (ExceptT e m) b                                                                                                          
monad-validate      >     • In the first argument of ‘(.)’, namely ‘getValidateT’                                                                                                                                  
monad-validate      >       In the second argument of ‘(>>=)’, namely ‘(getValidateT . f)’          
monad-validate      >       In the first argument of ‘ValidateT’, namely                                                                                                                                           
monad-validate      >         ‘(x >>= (getValidateT . f))’                                               
monad-validate      >     • Relevant bindings include                                                                                                                                                              
monad-validate      >         f :: a -> ValidateT e m b                                                  
monad-validate      >           (bound at src/Control/Monad/Validate/Internal.hs:299:19)              
monad-validate      >         x :: forall (s :: MonoMaybeS).                  
monad-validate      >              StateT (MonoMaybe s e) (ExceptT e m) a                                
monad-validate      >           (bound at src/Control/Monad/Validate/Internal.hs:299:13)                                                                                                                           
monad-validate      >         (>>=) :: ValidateT e m a                               
monad-validate      >                  -> (a -> ValidateT e m b) -> ValidateT e m b
monad-validate      >           (bound at src/Control/Monad/Validate/Internal.hs:299:15)                 
monad-validate      >     |                                                                              
monad-validate      > 299 |   ValidateT x >>= f = ValidateT (x >>= (getValidateT . f))                   
monad-validate      >     |