Generalization of maps: "Covariant" maps

[ske2004]

I need to convert map[...]Type to map[...]any, but it's not possible (I think)

My usecase is that I want to have a generic resource caching function where I can put resource into map[...]any while operating on a specialized map of resources.

But obviously converting it is impossible without changing the ABI. This is the same thing as with covariant dynamic arrays.

As far as I see the only way to solve this is through generics of some sort.