Stack overflow in stream-fusion library with GHC 6.10 RC

Regression from GHC 6.8.x to GHC 6.10 release candidate,

$ runhaskell Setup.lhs configure 
Configuring stream-fusion-0.1.1...
$ runhaskell Setup.lhs build     
Preprocessing library stream-fusion-0.1.1...
Building stream-fusion-0.1.1...
...
Data/Stream.hs:575:4:
    Warning: Pattern match(es) are non-exhaustive
             In the definition of `next':
                 Patterns not matched: (_ :!: (Just (L _))) :!: S2
[2 of 3] Compiling Data.List.Stream ( Data/List/Stream.hs, dist/build/Data/List/Stream.o )
stack overflow: use +RTS -K<size> to increase it

The stack overflow was not present with GHC 6.8.x

You can get the code here: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/stream-fusion

Trac metadata

Trac field	Value
Version	6.9
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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