Hi I'm working on a little experiment at the moment: using monadic QuickCheck to test the integration of my code and the database. I see some of my functions having properties like - given a database in this state, selectAll should return all rows, and so on. My initial attempt has worked nicely, and now I'm trying to test some more complicated properties, but I'm hitting a problem with overlapping primary keys, and this is because I'm not correctly cleaning up after each check. The simplest solution to this is to bracket property itself, and for that I turned to Control.Monad.Trans.Control in lifted-base, but I am struggling to actually write an instance for MonadBaseContol IO (PropertyM IO). It seems that PropertyM is a continuation monad transformer: newtype PropertyM m a = MkPropertyM { unPropertyM :: (a -> Gen (m Property)) -> Gen (m Property) } Given this, is it possible to even write an instance of MonadBaseControl? From the lifted-base documentation, it explicitly calls out ConT as *not* having instances, so I wonder if it can't be done. Sadly, I also lack intuition as to what MonadBaseControl really means - I think it means 'capture the state of this monad, so later we can go back to exactly the same state (or sequence of actions?)', but this is very flakey. So... is this possible, and if so how can I move forward? Thanks for any help or advice! - Ollie