panic with GeneralizedNewtypeDeriving and a .hs-boot file

With A.hs-boot:

module A where

data A
    deriving Show

We can get a panic:

$ ghc -c -XGeneralizedNewtypeDeriving A.hs-boot

A.hs-boot:5:13:ghc: panic! (the 'impossible' happened)
  (GHC version 6.9.20080716 for x86_64-unknown-linux):
        newTyConEtadRhs main:A.A{tc r6K}

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Trac metadata

Trac field	Value
Version	6.9
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown
Architecture	Unknown