Would not call that a massive migration but

https://code.facebook.com/security/fighting-spam-with-haskel...

This is a problem that is very well suited to Haskell, but it is a subset of general software development. Here it is worth the substantial overhead of making robust types as independent teams are making rules for this spam filter and typing can enforce order on it as they are probably easily categorized by type of filter. There are also quant developers that enjoy writing in OCaml, and AI devs too. But besides major companies using statically typed languages for some special teams, we don't see companies switching wholesale. Like I am still waiting for the day where $bigCompany says "we have hit so many type problems in our code that we have decided switching to staticaly typed languages will save us tons of money and are now requiring it".

It is really not in a companies interest to ever do a 'mass migration' excepting dire or takeover situatuons

I meant in the industry (as I believe the original comment intended), not one large enterprise migrating.

Well, in industry.. you know that clojure and haskell folks have more in common than different. A lot of the same folks move back and forth and care about the same things, just different ways to get there. I think the community size of clojure and haskell are sized very similarly and are also highly correlated. Any language graph you see that has both clojure and haskell, they always appear very close to each other.

Lest you forget, both fight against Java: https://trends.google.com/trends/explore?date=today%205-y&ge...

Industry is not doing a 'mass migration' to clojure, haskell, or any other language not in the top 5.

So the OP was wrong to claim a 'mass migration' in the first place

there is no such thing so don't get your expectations too high