[Haskell-cafe] haddock - 'could not find link destination"

i try to use haddock for documentation, but have no success. no output is produced. i assume i make some stupid mistake (not having used haddock before) help is appreciated! thank you andrew ------------------------------- i get the following error: $ haddock Hadtest2.hs Warning: Main: could not find link destinations for: GHC.Types.Int GHC.Base.String Hadtest2.hs is a simplistic test program with some parts copied from the haddock manual: module Main (square, this) where -- | a constant this :: String this = "this" -- |The 'square' function squares an integer. square :: Int -> Int square x = x * x main = do putStrLn $ "test " ++ show (square 4) return () --