[dwohnitmok]

I think Typescript has both a complex and expressive type system. When I say "advanced" I'm talking about expressiveness. It is more expressive than Scala and (absent a laundry list of GHC extensions) Haskell.

I agree that Typescript certainly seems like a tower of hacks next to Idris.

Yet somehow it's pulled off a reputational miracle: having a more expressive type system than Haskell but not being regarded as an "advanced" language. Unfortunately I think that's mainly due to the ways the type system can be undermined, but it's still a useful nugget I ponder from time to time.

> It doesn't even give you strong guarantees. There is a reason why Hindley-Milner type systems are called the sweet spot of static typing.

HM by itself doesn't give you strong guarantees (see e.g. the ML family of languages which have comparatively weak guarantees next to Haskell). That's really due to other language and standard library decisions acting in concert.

HM type systems are often the sweet spot for static typing not because of the guarantees they offer, but because of the global type inference it yields. More expressive extensions of HM often break global type inference in some way.