#15696: Derived Ord instance for enumerations with more than 8 elements seems to be incorrect -------------------------------------+------------------------------------- Reporter: mrkkrp | Owner: (none) Type: bug | Status: patch Priority: highest | Milestone: 8.6.2 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): Phab:D5196 Wiki Page: | -------------------------------------+------------------------------------- Comment (by osa1): Thinking about this more. I think the only case where we can actually avoid entering the argument of `dataToTag#` is when the argument is a static closure. For anything else (a dynamic closure, a CAF) we need to enter it. I don't know how often people do `dataToTag# C` (for some constructor `C`), perhaps it's fine to always enter it. If it is then we can remove the special case for `dataToTag#` in CorePrep and in the codegen (in Cmm) we can just enter the argument. If we decide to do that then perhaps we should also revisit the `getTag` and remove the bang pattern on its argument. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15696#comment:24 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler