ghc: panic! (the 'impossible' happened): Missing alternative

When I include the -auto-all option (in addition to -prof) on the entry for Main in my Cabal file, I get the ghc panic message below. Full compile output attached.

[10 of 10] Compiling Main             ( Rdf4hParseMain.hs, dist/build/rdf4h/rdf4h-tmp/Main.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 6.10.1 for x86_64-unknown-linux):
	Missing alternative
    main:Main.OutputFormat{d r16LZ}
    (main:Main.Help{d r16M9}, [], lvl_s17ar{v} [lid])
    (main:Main.Debug{d r16M7}, [], lvl_s17as{v} [lid])
    (main:Main.Version{d r16M5}, [], lvl_s17at{v} [lid])

To reproduce the bug, check out a tagged version of the code using:

darcs get -t 'ghc bug report' http://protempore.net/rdf4h

And then edit the cabal file by adding "-prof -auto-all" to the library and main entries, and you should see what I see above if it's reproducible. It compiles fine if the options are only added to the library block, and it compiles fine if '-prof' but not '-auto-all' is added to the executable block, but fails when '-prof' and '-auto-all' are both added to the executable block.

Trac metadata

Trac field	Value
Version	6.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture