deriving Read leads to "no parse"

The program

------ Start Offending Program -----
module Main
where

data T = C (Maybe Int) Int
       deriving (Show, Read, Eq)

main = 
  do
    let v = C Nothing 1
    print v
    print $ read (show v) == v
------ End Offending Program -----

leads to

AttitudeAdjuster chak 5 (~/haskell): ghc Main.hs
AttitudeAdjuster chak 6 (~/haskell): ./a.out 
C Nothing 1

Fail: Prelude.read: no parse
AttitudeAdjuster chak 7 (~/haskell): 

Experimentation suggests that it is the `Maybe' type
appearing in the type for which Read is derived that
causes the problem.  This problem does *not* occur with
GHC 5.04; ie, has been introduced with patchlevel 1. 
(I am not sure whether it is a problem in the Prelude
or the deriving mechanism.)

This bug is pretty serious for me, as it utterly breaks
C->Haskell.

/me waits for GHC 5.04.2...

Trac metadata

Trac field	Value
Version	5.04.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	ResolvedFixed
Component	Compiler
Test case
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