Attempting to do foreign import with unboxed tuple return type causes GHC panic

stefan@stefans:/tmp$ ghc -ddump-asm -fglasgow-exts X.hs
ghc-6.7.20070829: panic! (the 'impossible' happened)
  (GHC version 6.7.20070829 for i386-unknown-linux):
resultWrapper
    (# base:GHC.Prim.Int#{(w) tc 3G},
       base:GHC.Prim.Int#{(w) tc 3G},
       base:GHC.Prim.Int#{(w) tc 3G} #)

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

stefan@stefans:/tmp$ cat X.hs
module X where
import GHC.Exts
foreign import ccall unsafe "foo" foo :: Int# -> Int# -> Int# -> (# Int# , Int# , Int# #)
stefan@stefans:/tmp$ 

1. 6.1 and 6.4.2 are also affected.

Trac metadata

Trac field	Value
Version	6.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (FFI)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	sorear
Operating system
Architecture