Given the code
> type C a = D a -> a
> newtype D a = DD (D_ a)
> type D_ a = C (Maybe a)
Both ghc 3.02 and 4.01 (solaris binaries from the web site) say:
Entered a `black hole': the program has a cyclic data dependency.
The compilers are happy if "newtype" is changed to "data".
Paul.
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Dr. Paul Callaghan (Research Assistant) Email: [EMAIL PROTECTED]
Computer Assisted Reasoning Group, Department of Computer Science, Durham
http://www.dur.ac.uk/~dcs7ttg
