#14969: panic on incorrect syntax -------------------------------------+------------------------------------- Reporter: johnleo | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- With a fresh build of 8.5: {{{ GHCi, version 8.5.20180323: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /Users/leo/.ghci Prelude> 3 _ 4 ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.5.20180323 for x86_64-apple-darwin): ASSERT failed! 2 1 t_a4j6[tau:1] Maybe a_a4j7[tau:2] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1157:37 in ghc:Outputable pprPanic, called at compiler/utils/Outputable.hs:1213:5 in ghc:Outputable assertPprPanic, called at compiler/typecheck/TcMType.hs:720:54 in ghc:TcMType }}} I believe this fails in earlier versions as well, but I haven't tested it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14969 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler