In getting the dtd library to compile with recent versions of conduit (yes, I know that it's deprecated and Michael longer supports it, but we still need it), we came across the following bit of code: -- (snip) -- CI.ConduitM $ addCatch $ CI.unConduitM src0 where -- (snip) -- addCatch :: (MonadThrow m, MonadBaseControl IO m) => CI.Pipe l i o u m r -> CI.Pipe l i o u m r addCatch (CI.HaveOutput src close x) = CI.HaveOutput (addCatch src) (addCatch' close) x addCatch (CI.NeedInput p c) = CI.NeedInput (addCatch . p) (addCatch . c) addCatch (CI.Done r) = CI.Done r addCatch (CI.PipeM msrc) = CI.PipeM (addCatch' $ liftM addCatch msrc) addCatch (CI.Leftover p i) = CI.Leftover (addCatch p) i addCatch' m = m `Lifted.catch` throw rr We adapted it to the new ConduitM type simply by changing the first line to: CI.ConduitM $ addCatch . CI.unConduitM src0 Not bad, a diff of exactly one character. It compiles and seems to work. Does this sound reasonable? Obviously, we would love to get rid of this use of conduit internals. addCatch seems like a general operation, not specific to this library. Is there a way to do this in modern conduit without dipping into internals? If not - can we propose to add it? Thanks, Yitz