Correct the implementation of padTo

Author: philderbeast

Cabal/src/Distribution/GetOpt.hs

@@ -117,12 +117,14 @@ usageInfo header (map flattenNames -> options) = unlines (header : table)
     rowOption name = indent : padTo (nameWidth - 2) name
 
 -- | Pad a string to a given length with spaces.
+-- >>> padTo 5 "123"
+-- "123  "
 --
--- If the string is longer than the given length, it is truncated.
+-- If the string is longer than the given length, it is not truncated.
 -- >>> padTo 3 "12345"
--- "123"
+-- "12345"
 padTo :: Int -> String -> String
-padTo n x = take n (x ++ repeat ' ')
+padTo = flip $ foldr (\ch rest n -> ch : rest (n - 1)) (`replicate` ' ')
 
 -- | Flatten the short and long option names into a single string for display.
 flattenNames :: OptDescr a -> OptHelp