Today we start to wrap up 24 Days of GHC Extensions with the final guest post, this time from Mathieu Boespflug of Tweag I/O. Mathieu, along with his colleagues Facundo Domínguez and Alexander Vershilov, has been working with the GHC team on a new extension - in fact, so new, you won’t even find this in a stable release of GHC! In today’s post, we’ll have a look at a new type of pointer that can b