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fused-effects / fused-effects

A fast, flexible, fused effect system for Haskell

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IO-specific sendM synonym

robrix opened this issue · comments

commented

#82 is closed but the issue still crops up: if you are using Lift IO constraints and are using functions constrained to MonadIO (e.g. defined in some other library) then you have to add MonadIO constraints too, because sendM doesn’t specify that you want m to be IO and neither does the function you’re lifting.

commented

I think we still want a sendIO synonym for sendM with its type restricted to IO:

sendIO :: Has (Lift IO) sig m => IO a -> m a
sendIO = sendM

Another alternative I’ve tried is a LiftIO type which provides both Algebra & MonadIO instances, the latter implemented via Has (Lift IO) sig m, but it’s heavier-weight and is harder to justify including in the library.