>Which is pretty much my problem with it: this sort of thing can be fun, feels intellectually stimulating. But the added power doesn't make coding easier or make the code more sound.
In practice nobody goes too crazy with it. You have a problem with a feature almost nobody uses. It's there and Range<N> is like the upper bound of complexity I've seen in production but that is literally extremely rare as well.
There is no "temptation" of coding complex logic in it at all as the language doesn't promote these features at all. It's just available if needed. It's not well known but typescript types can be easily used to be 1 to 1 with any hindley milner variant. It's the reputational baggage of JS and frontend that keeps this fact from being well known.
In short: Typescript is more powerful then hindley milner, a subset of it has one to one parity with it, the parts that are more powerful then hindley milner aren't popular and used that widely nor does the flow of the language itself promote there usage. The feature is just there if you need it.
If you want a language where you do this stuff in practice take a look at Idris. That language has these features built into the language AND it's an ML style language like haskell.
I have definitely worked in TS code bases with overly gnarly types, seen more experienced devs spend an entire workday "refactoring" a set of interrelated types and producing an even gnarlier one that more closely modeled some real world system but was in no way easier to reason about or work with in code. The advantage of HM is the inference means there is no incentive to do this, it feels foolish from the beginning.
In practice nobody goes too crazy with it. You have a problem with a feature almost nobody uses. It's there and Range<N> is like the upper bound of complexity I've seen in production but that is literally extremely rare as well.
There is no "temptation" of coding complex logic in it at all as the language doesn't promote these features at all. It's just available if needed. It's not well known but typescript types can be easily used to be 1 to 1 with any hindley milner variant. It's the reputational baggage of JS and frontend that keeps this fact from being well known.
In short: Typescript is more powerful then hindley milner, a subset of it has one to one parity with it, the parts that are more powerful then hindley milner aren't popular and used that widely nor does the flow of the language itself promote there usage. The feature is just there if you need it.
If you want a language where you do this stuff in practice take a look at Idris. That language has these features built into the language AND it's an ML style language like haskell.