Thanks for that, I wasn’t fully aware of the history of ML! Very interesting (and very impressive that this is just one of Milner’s contributions).

I started with Haskell, where the main influence besides ML was Miranda. (If I remember correctly, Haskell was only created because Miranda was proprietary; similar to BitKeeper and Git.) I guess Miranda’s main innovation was lazy evaluation. That has certainly been influential but outside Haskell I don’t think it’s ever had widespread adoption in the same way as ML-style typing and type inference.

* Every responsible programming language designer could have taken on board ML's lessons sincen, and it's an interesting historical question why this did not happen.*

Agreed! But maybe it is happening, it’s just that it’s taken 30 years instead of the 5 or 10 one might have expected?