Actually, changes to the compiler hardly ever break anything. I recently upgraded four compiler versions in a row and apart from a bug and some warnings the co

Actually, changes to the compiler hardly ever break anything. I recently upgraded four compiler versions in a row and apart from a bug and some warnings the compiler didn't force any changes at all. It's primarily changes to libraries that introduce churn. https://h2.jaguarpaw.co.uk/posts/ghc-8.10-9.6-experience-report/ https://h2.jaguarpaw.co.uk/posts/ghc-8.10-9.6-experience-rep... (DeepSubsumption wouldn't have been a problem if we'd specified Haskell2010, as we should have.)