[ ghc-Bugs-1232479 ] panic: "Non-exhaustive patterns in function zip_ty_env"

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Bugs item #1232479, was opened at 2005-07-04 17:39
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Category: Compiler (Type checker)
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: panic: "Non-exhaustive patterns in function zip_ty_env"

Initial Comment:
ghc-6.4: panic! (the `impossible' happened, GHC version
6.4):
        types/Type.lhs:(1107,0)-(1108,77):
Non-exhaustive patterns in function zip_ty_env

The same file compiles fine with GHC 6.2.2.

Unfortunately I don't have a small example of this
behaviour. I can send you the whole library if you need
it, but it is not painless to get to this point.

It would be great if you could give me some pointers
about where the bug might lie - it uses MPTC instances,
recursive newtypes and the FFI.

thanks,
peter, peteg at unsw.edu.au

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