I see this repeated again and again. It's wrong.

The "solution" to the generics problem is to not try to do anything that is generic, but do it specific: re-write that sort every time you need it for a new type.

People who have some experience in Go seem to tell that when you go this path you actually realize that you won't write them hundreds of time as was feared; it's completely manageable. Plus, you have your "sort" re-implementation right next to the struct definition, so you know it is sortable.