#15517: haddock triggers panic in trimJoinCont -------------------------------------+------------------------------------- Reporter: sjakobi | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Running haddock on the [https://github.com/VictorCMiraldo/generics-mrsop `generics-mrsop`] package results in {{{ haddock: panic! (the 'impossible' happened) (GHC version 8.4.3 for x86_64-unknown-linux): completeCall fail_av9P Select nodup wild_00 Stop[BoringCtxt] Rep Singl (El FamRoseInt) (Lkup ix CodesRoseInt) Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in ghc:Outputable pprPanic, called at compiler/simplCore/Simplify.hs:1533:9 in ghc:Simplify }}} The same problem affects 8.6.1 and HEAD, but not 8.2.2. The panic seems to stem from [https://github.com/ghc/ghc/blob/64c71ce956af3af593a46ef0d615c7f6fe6ecece/com... this catch-all in `trimeJoinCont`]. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15517 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler