I think you meant to forward to the libraries mailing list, not the
ghc-devs one
On Tue, Jun 1, 2021, 18:01 Baldur Blöndal
This is to advertise the proposal (https://gitlab.haskell.org/ghc/ghc/-/issues/19922) to add a superclass to the MonadTrans type class in Control.Monad.Trans.
A Monad transformer 'trans' lifts a 'Monad m' to a 'Monad (trans m)'.
This proposal code-ifies that with a superclass constraint, an impliciation constraint enabled by the recent extension QuantifiedConstraints:
class (forall m. Monad m => Monad (trans m)) => MonadTrans trans where ..
This is the main motiviating example of the Quantified Class Constraints paper https://gkaracha.github.io/papers/quantcs.pdf _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs