-keep-tmp-files does not keep all temporary files

I invoke ghc like this:

ghc --make -cpp -pgmLlhs2TeX -optL --pre -pgmPcpphs.compat -keep-tmp-files Functor.lhs

However, even with the -keep-tmp-files option enabled, ghc still does not keep the file it references in the error message below, which is annoying because it makes it less convenient to debug this error:

Chasing modules from: Functor.lhs
Skipping  Category         ( ./Category.lhs, ./Category.o )
Compiling Functor          ( Functor.lhs, Functor.o )

/tmp/ghc16196.lpp:15:0: parse error (possibly incorrect indentation)

Trac metadata

Trac field	Value
Version	6.4.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Driver
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-keep-tmp-files does not keep all temporary files