I had a leader once who told us outright any mention that Haskell was a motivation for the job is a red flag. He explicitly didn't want people who were significantly interested in us due to our Haskell use. Turns out Haskellers tend to be drawn to Haskell companies in no small part due to Haskell, so we failed to hire basically anyone after the leader came aboard (most were all yes but a single no from the leader) and then the leader pushed us to move off Haskell citing difficulty hiring and that he had hired people in another office who didn't know or want to learn Haskell. Dirty tactics.