The following (admittedly rather small :-) fragment from Manuel's
GTK+-binding fails to compile with ghc-4.02:
---------- Foo.hs ----------------------------------------------
module Foo where
data Bar = Baz deriving Enum
----------------------------------------------------------------
panne@liesl:~ > ghc -c Foo.hs
panic! (the `impossible' happened):
tcLookupValue: PrelBase.zg{-rRR,j-}
Please report it as a compiler bug to [EMAIL PROTECTED]
----------------------------------------------------------------
Using -O is even more confusing:
----------------------------------------------------------------
panne@liesl:~ > ghc -c Foo.hs -O
Foo.hs:2:
No instance for `Ord Int' arising from use of `>=' at Foo.hs:2
Foo.hs:2:
No instance for `Ord Bar' arising from use of `>' at Foo.hs:2
----------------------------------------------------------------
The problems vanish if 'deriving Enum' is replaced with 'deriving
(Eq,Ord,Enum)'. An old ghc-3.02 works, too.
Cheers,
Sven
--
Sven Panne Tel.: +49/89/2178-2235
LMU, Institut fuer Informatik FAX : +49/89/2178-2211
LFE Programmier- und Modellierungssprachen Oettingenstr. 67
mailto:[EMAIL PROTECTED] D-80538 Muenchen
http://www.pms.informatik.uni-muenchen.de/mitarbeiter/panne
