modules and re-export

[Peter Thiemann]

I have a little question about the following two modules. Suppose you
want to write your own variant of the prelude that redefines a couple
of names but leaves all the rest unchanged. The Haskell report says
that the following should work:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module BUG2A (module BUG2A, module Prelude) where

import Prelude hiding (head)

head = "HEAD"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This overrides the definition of head and should reexport head along
with everything imported from the Prelude. Hugs98/feb2001 loads it
happily and says head :: [Char]
Now, I want to use this module as an alternative prelude:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
module BUG2B where

import qualified Prelude
import BUG2A
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Unfortunately, this does not behave as (I think) it should:

Reading file "BUG2B.hs":
Parsing........................................................................
ERROR "BUG2B.hs": Entity "head" imported from module "BUG2A" already defined in module "Prelude"

However, this should be legal from my reading of the report.

Any help appreciated.

-Peter