Some class instances from the base monad could not pass through SeldaT, ie. SeldaT b (StateT s IO) did not have a MonadState s instance,
SeldaT could only be used as outermost element in the transformer stack, ie. StateT s (SeldaT b IO) did not have a MonadSelda instance,
The use of onException made it unsafe to use a base monad that uses any form of short-circuiting that is not an exception, ie. ExceptT.
Fixing that last point requires using generalBracket introduced in exceptions-0.9, so I had to bump the dependency requirement. I am not sure how this impacts the range of GHC versions that can be supported.
Supporting ExceptT/MonadError is rather important for applications based on servant.
This PR fixes the following limitations:
SeldaT, ie.SeldaT b (StateT s IO)did not have aMonadState sinstance,SeldaTcould only be used as outermost element in the transformer stack, ie.StateT s (SeldaT b IO)did not have aMonadSeldainstance,onExceptionmade it unsafe to use a base monad that uses any form of short-circuiting that is not an exception, ie. ExceptT.Fixing that last point requires using
generalBracketintroduced inexceptions-0.9, so I had to bump the dependency requirement. I am not sure how this impacts the range of GHC versions that can be supported.Supporting
ExceptT/MonadErroris rather important for applications based on servant.