#9092: ghc: panic! (the 'impossible' happened) -----------------------------------+--------------------------------------- Reporter: alex404 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: panic | Operating System: Linux impossible | Type of failure: Compile-time crash Architecture: | Test Case: Unknown/Multiple | Blocking: Difficulty: Unknown | Blocked By: | Related Tickets: | -----------------------------------+--------------------------------------- I'm not sure *why* this is happening, but I know where. The code for this library is available here: http://hub.darcs.net/alex404/hsl-random So as is, I can run the script called multivariate and get the expected results, but when I try to compile I get ghc: panic! (the 'impossible' happened) (GHC version 7.8.2 for x86_64-unknown-linux): attempt to prod-split usage call demand C(C1(U(U,U,U,U,U,U))) If at line 317 in Scientific.Random.Distributions.hs, I replace the statement sgma = ... with sgma = undefined, the code will compile, though obviously it cannot be used. If I transform the code in other ways which are meant to preserve the results, I can get it to compile, but then the script hangs. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9092 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler