#14308: GHC panic with invalid expression ----------------------------------------+--------------------------------- Reporter: d6e | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: MacOS X Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- Hi, I recently discovered this expression causes GHC to panic. Shouldn't it handle this more gracefully? Perhaps saying something like "That expression is not valid. <Further Explanation>" Invalid expression: {{{#!hs g :: (a->b) a }}} {{{ Prelude> g :: (a->b) a ghc: panic! (the 'impossible' happened) (GHC version 8.2.1 for x86_64-apple-darwin): repSplitAppTys a_a1Lz[sk:1] b_a1LA[sk:1] [] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1133:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1137:37 in ghc:Outputable pprPanic, called at compiler/types/Type.hs:808:9 in ghc:Type Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14308 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler