nameModule panic when building numbers package

[simonmar]

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}

[simonpj]

I'm on this

[simonpj]

Thanks for a helpful report. I've fixed this, but it was a while ago now. I think this is the relevant patch

Thu May  6 17:41:35 BST 2010  simonpj@microsoft.com
  * Find the correct external ids when there's a wrapper
  
  We were failing to externalise the wrapper id for a function
  that had one.

    M ./compiler/main/TidyPgm.lhs -2 +9

I have not added a regression test because it's quite hard to elicit the bug with a small program. But I think we are good now.

Simon