Your map was very formative for me when I was exploring metal, thanks a lot !
I would love for this Map to be expanded to modern subgenres. There are lot's of subgenres that completely changed in the last decades (notably, the *cores and the tech* ...)
HM is not complex type inference. In fact, among all the approaches you cite, it leads to the simplest type system and the simplest implementation. Moreover, there are lot's of courses, reference implementations, and reasonable extensions for a wide array of features (structural subtyping, qualified types, etc). There are even type-system libraries to make it easy to implement (like Inferno).
When new programmer discover ML-family language, they are often stunned by how lightweight it feels, because you don't have to annotate anything. If your types are not structurally too complicated and you want something really easy to use, HM is still the nicest experience.
Naturally, it's all a tradeoff, and if you want specific features (chiefly: borrows, high-order types, overloading, or Typescript-like features), you will need to abandon complete inference (and use something like bidirectional, most likely).
I'm going to be contrarian: Yes, you should learn about type systems if you want to design a programming language, and decide in full conscience what you need. At the very least, it will give you a concrete idea of what safety means for a programming language.
It doesn't mean you have to use an advanced one, but your choice choose be based on knowledge, not ignorance.
A lot of harm; including the billion dollar mistake, has been done by badly designed type systems from the Java/C/C++ family.
I was looking for a way to turn my (soon-to-be-defended) PhD thesis into an epub, and investigated the various LaTeX2Html converters.
I was pretty disappointed when I realized that all of them are terrible and have no hope of handling my manuscript. My current solution is to create a rendering of my thesis in a5 format. :/
This look quite a bit better, so here is the question: what do you not support at the moment?
I would love for this Map to be expanded to modern subgenres. There are lot's of subgenres that completely changed in the last decades (notably, the *cores and the tech* ...)
And it's definitely missing Thall (https://www.youtube.com/watch?v=AtV9pcHh8vM). :D