I'm not sure if I'm the first to notice, but the Haskell quicksort function is wrong, because it mishandles NaN: main = let nan = 0.0 / 0.0 in

I'm not sure if I'm the first to notice, but the Haskell quicksort function is wrong, because it mishandles NaN: main = let nan = 0.0 / 0.0 in do putStrLn $ show $ quicksort [nan, 1.0, 2.0, 3.0] putStrLn $ show $ quicksort [1.0, nan] [NaN] [1.0] Sort routines should not return a list of a different length than their input.