I'm curious, what sorts of issues arise with complex types that Haskell-like syntax handles better? (Genuinely curious here -- I've written a little Haskell but am by no means an expert...)

IMHO a Rust-style type `Option<HashMap<String, Vec<u32>>>` is a little noiser than the Haskell-style type `Maybe (Map String [Int])`, but not fatally so. Maybe there are much worse cases though?