Type system of Fortnite's Verse language
Tangential, and because I had to look it up:<p>> <i>Verse has been designed by some people who really know what they’re doing: Lennart Augustsson,
Joachim Breitner, Koen Claessen, Ranjit Jhala, Simon Peyton Jones, Olin Shivers, Tim Sweeney</i><p>The listed people are all luminaries of the functional programming world (and adjacent, like theorem proving and software verification), particularly Haskell. Hell, Simon Peyton Jones is one of the <i>creators</i> of Haskell.<p>My point is, the creators of Verse aren't just a bunch of coders (pejorative) who felt like creating Yet Another Language.