#8882: internal error (deriving generic / cyclical imports?) ----------------------------------+------------------------------- Reporter: mf825 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: panic | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: GHCi crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+------------------------------- Hi everybody, I often get compiler crashes in my larger and less well-maintained projects of this sort: ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for x86_64-unknown-linux): tcIfaceGlobal (local): not found: <<details unavailable>> This happened on earlier 7.* ghc versions (debian 64bit), and from the counter-example I have condensed today my vague guess is that it has something to do with cyclical imports and -XDerivingGeneric or some other type system related language extension. I witnessed this in both ghc and ghci, but the counter-example is in ghci. I want to investigate this further later, but in the hope that somebody can immediately see what's wrong, I decided to open this ticket with my preliminary findings. Just unpack and run ./crash.sh. (Possibly you don't need to populate the sandbox and can crash it manually in your environment right away.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8882 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler