#14344: `ghc: panic!` when loading module -------------------------------------+------------------------------------- Reporter: javi | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Keywords: | Operating System: MacOS X Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I'm learning Haskell from an online book (haskellbook.com) and when I loaded an answers module, this happened: {{{#!hs Prelude> :l ex.hs [1 of 1] Compiling Ex ( ex.hs, interpreted ) ghc: panic! (the 'impossible' happened) (GHC version 8.2.1 for x86_64-apple-darwin): repSplitAppTys a_a1qJ[sk:1] Bool [] 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
}}} notice that the Prelude module got unloaded. The source code for my `ex.hs` module: {{{#!hs module Ex where import Data.Char myAny :: (a -> Bool) [a] -> Bool myAny pred [] = False myAny pred (x:xs) = pred x || myAny pred xs }}} You'll notice that I missed a `->` in `myAny`'s type signature. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14344 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler