Data.ByteString.Lazy.Char8's readInt does no bounds checking

I think it should be failing with Nothing if given a string of digits that's too long.

~ $ ghci
   ___         ___ _
  / _ \ /\  /\/ __(_)
 / /_\// /_/ / /  | |      GHC Interactive, version 6.6, for Haskell 98.
/ /_\\/ __  / /___| |      http://www.haskell.org/ghc/
\____/\/ /_/\____/|_|      Type :? for help.

Loading package base ... linking ... done.
Prelude> :m +Data.ByteString.Lazy.Char8 
Prelude Data.ByteString.Lazy.Char8> readInt (pack "99999999999999999999")
Just (7766279631452241919,LPS [])