Afaik that is true of traditional HM, but fortunately there was a big advancement in inferring subtypes w/ Dolan's Algebraic Subtyping a few years ago! It's not

Afaik that is true of traditional HM, but fortunately there was a big advancement in inferring subtypes w/ Dolan's Algebraic Subtyping a few years ago! It's not nearly as fast as HM (O(n^3) worst case) but generally fast enough in real code