#15696: Derived Ord instance for enumerations with more than 8 elements seems to be incorrect -------------------------------------+------------------------------------- Reporter: mrkkrp | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): That's terrible! The following all produce the same (wrong) restul {{{ S.fromList (map f [ () | _ <- [1..10] ]) -- T2,T2 S.fromList [f (), f ()] -- T2,T2 S.fromList [f (), f (), f()] -- T2,T2 }}} However this works fine {{{ f () `S.insert` (f () `S.insert` S.empty) }}} The comparison operations generated by `deriving` look ok to me. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15696#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler