#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 RyanGlScott): Apologies, I meant to mention in comment:6 what `wumbo` actually is: it's a stripped down version of `insert` intended to highlight that it appears to behave differently between GHC 8.4.3 and 8.6.1. The semantics of `wumbo` differs from that of `insert`, but here is the important bit: {{{ $ /opt/ghc/8.4.3/bin/ghc -O2 -fforce-recomp Bug.hs && ./Bug [1 of 1] Compiling Main ( Bug.hs, Bug.o ) Linking Bug ... Bin T2 Tip Tip $ /opt/ghc/8.6.1/bin/ghc -O2 -fforce-recomp Bug.hs && ./Bug [1 of 1] Compiling Main ( Bug.hs, Bug.o ) Linking Bug ... Bin T2 Tip (Bin T2 Tip Tip) }}} GHC 8.4.3's answer is definitely the correct one, since the only way you'd get 8.6.1's answer is by hitting the `GT` case of `wumbo` (which shouldn't happen if you're comparing `T2` to `T2`). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15696#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler