I’m collecting a list of all breaking changes between GHC 9.10 and 9.12, that is, anything that you have to change (except just bounds) to get code that previously compiled with 9.10 to compile with 9.12. My hope is that it will feed into a processes of making breaking changes less severe in the future. If you have come across any breaking changes please let me know here or in an issue or PR on the repo.
See also: