Template Haskell currently has runIO :: IO a -> Q a , which allows you to run IO actions with a guarantee of IO effects' ordering in a single splice (but not necessarily the order in which all the Q splices are run). If runIO is indeed a monad morphism, then there is a law-abiding MonadIO Q instance that could be added to transformers: instance MonadIO Q where liftIO = runIO This would be useful for dealing with monad transformer stacks with Q as the base monad (for an example, see genifunctors (https://github.com/danr/genifunctors/blob/4677bb57423b1b380ce9b50cc3d765a5c4...). The only catch is that transformers would have to depend on template-haskell. I think this would be okay since no quasiquotation is involved, but I wanted to hear others' opinions. Ryan