#8383: "tagToEnum# (0# ==# 1#) :: Bool" causes CASEFAIL in ghci ---------------------------------+---------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.7 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 (amd64) Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+---------------------------------- Comment (by rwbarton): It seems that the issue is in the bytecode generator for `tagToEnum#`, which has been wrong since at least ghc 6.8.2 and probably since it was added in 2001. However, an application of `tagToEnum#` to a constant apparently gets constant-folded away before the interpreter sees it, which is probably why nobody ever noticed before `tagToEnum#` became used in derived Eq instances. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8383#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler