I find that hlint is a great tool for pointing out where your code can be improved, but sometimes its suggestions are... interesting. Case in point, it just recommended changing

map (\(a, b) -> {- ...stuff... -}) $ zip as bs

to

zipWith (curry (\(a, b) -> {- ...stuff... -})) as bs

instead of

zipWith (\a b -> {- ...stuff... -}) as bs