This package provides Template Haskell helpers for fused-effects. The makeSmartConstructors splice, given the name of a GADT defining an effect, iterates through the possible constructors and generates functions that construct effects using send. That is to say, given the standard State type:

data State s m k where
  Get :: State s m s
  Put :: s -> State s m ()

calling makeSmartConstructors ''State generates the following code (cleaned up a little from the native Template Haskell output):

get ::
  forall s sig m
  Has (State s) sig m =>
  m s
get = send Get
{-# INLINEABLE get #-}
 put ::
  forall s sig m.
  Has (State s) sig m =>
  s ->
  m ()
put a = send (Put a)
{-# INLINEABLE put #-}

Bug reports are welcome on the issue tracker.