Jurriaan, Ben I have a MR up for #17775, which implements the now-accepted GHC proposal to simplify subsumption. https://gitlab.haskell.org/ghc/ghc/merge_requests/2600 However, it requires some eta expansions in haskeline, and maybe other packages. I don't know how to do that. Could you, or another member of the GHC support team, help do this? We want a MR we can validate on its own before committing, of course. Jurriaan has all the necessary library patches. We should not commit to HEAD until there has been some code review, though. Moreover as we know, when committed, it'll break a number of packages, so we need to broadcast a warning, along with the patches Jurriaan has to fix them. I'm not sure when and how to do that. Thanks! Simon