Network.firstSuccesful: 'throw' vs 'throwIO' usage

[Herbert Valerio Riedel]

Hello,

while reading over the source code of network[1], I noticed a use of 'throw' where I'd
expect 'throwIO':

    import qualified Control.Exception as Exception

    catchIO :: IO a -> (Exception.IOException -> IO a) -> IO a
    catchIO = Exception.catch

    -- Returns the first action from a list which does not throw an exception.
    -- If all the actions throw exceptions (and the list of actions is not empty),
    -- the last exception is thrown.
    firstSuccessful :: [IO a] -> IO a
    firstSuccessful [] = error "firstSuccessful: empty list"
    firstSuccessful (p:ps) = catchIO p $ \e ->
        case ps of
            [] -> Exception.throw e
            _  -> firstSuccessful ps



...so, is `throw` used properly in the code above, or should it rather
be `throwIO`?


 [1]: http://hackage.haskell.org/packages/archive/network/2.3.1.0/doc/html/src/Network.html#firstSuccessful