I wanted to use the CPS version of RWST from transformers but the latest release of mtl (2.2.2) does not provide instances yet. Looking at the github repo I see that the missing instances were added two years ago, with no release since then. With all due respect to the maintainers and developers, this is disappointing. The ticket for release 2.3 mentions the following TODO items: - Document AccumT and SelectT - MonadAccum (including documentation) - MonadSelect (including documentation) These all concern new additions made in the last two years, some of them quite recent. This style of package maintenance doesn't make sense to me. Why add new features before releasing what's been done years ago? Why accept patches with additional features in the mainline if they are apparently incomplete (e.g. missing documentation) if that blocks progress toward a release? The obvious solution (need i spell it out?) is to move all new features that aren't mature yet to feature branches until they are ready for the mainline. Then take the work that is complete and release that. What's the big deal? Add a few lines to the changelog, bump the version number, upload, announce it on the mailing list. If you don't like to rebase the master branch, fork off a release branch at the appropriate point in the history and do the release on that branch, cherry-picking later patches from master as necessary. (Maintaining a release branch per major version bump is good practice anyway and requires only minimal extra work.) Don't fall into the trap of the perfect becoming the enemy of the good. No release is perfect, nor does it have to be. You can always make patch releases. If you make a mistake and the release is broken, just mark it as such on hackage, so cabal won't pick it by default. Needless to say, none of this is in any way new or original. Cheers Ben -- I would rather have questions that cannot be answered, than answers that cannot be questioned. -- Richard Feynman