#11822: Pattern match checker exceeded (2000000) iterations -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc3 Resolution: | Keywords: | PatternMatchWarnings Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by NeilMitchell): I've ran into this two times, both regressions since GHC rc3. The two cases are: * https://github.com/ndmitchell/hlint/blob/master/src/HSE/Bracket.hs needBracket (currently at a438ba0e45697e65bbcd9fb996d350b07394a45f) * https://github.com/ndmitchell/derive/blob/master/src/Language/Haskell/TH/Pee... peep (currently at 6a703a9f71986232bbb1e54853a548af2b53b706) Is there any recommendation on how I can avoid this warning without CPP in a way that works on older versions of GHC? In contrast to the original reporter, I do not welcome that GHC emits this warning. It seems a warning about GHC, not my code, and not something that I can do much about, other than turn off warnings, which seems a little sad. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11822#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler