#15586: Compilation panic! (the 'impossible' happened) -------------------------------------+------------------------------------- Reporter: subaruru | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- See attached zip for entire project causing error. I'd imagine it's pretty reproducible, just call stack build. I'm running standard lts-12.8 and it's just two small files that don't do anything yet! Also included is panicmessage.txt showing the exact output, crucially: {{{ ghc: panic! (the 'impossible' happened) (GHC version 8.4.3 for x86_64-unknown-linux): piResultTy * v_XabT Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in ghc:Outputable pprPanic, called at compiler/types/Type.hs:947:35 in ghc:Type }}} Oh and sysinfo {{{ uname -a Linux @@@ 4.16.11-100.fc26.x86_64 #1 SMP Tue May 22 20:02:12 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15586 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler