nameModule panic when building numbers package

Building the numbers-2009.8.9 package from Hackage with yesterday's GHC HEAD (2010-03-15):

~/tmp/numbers-2009.8.9 > ./Setup build
Preprocessing library numbers-2009.8.9...
Building numbers-2009.8.9...

Data/Number/Fixed.hs:1:16:
    Warning: -fscoped-type-variables is deprecated: use -XScopedTypeVariables or pragma {-# LANGUAGE ScopedTypeVariables #-} instead
[7 of 9] Compiling Data.Number.CReal ( Data/Number/CReal.hs, dist/build/Data/Number/CReal.o )
ghc-stage2: panic! (the 'impossible' happened)
  (GHC version 6.13.20100315 for x86_64-unknown-linux):
        nameModule $w$cnegate{v r2zR}

Trac metadata

Trac field	Value
Version	6.13
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture