#8169: ghc: panic! (the 'impossible' happened) ----------------------------------+--------------------------------- Reporter: guest | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.1 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+--------------------------------- ghc: panic! (the 'impossible' happened) (GHC version 7.4.1 for x86_64-unknown-linux): compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed for pattern Data.Maybe.Just (inst_tyvars, _, SrcLoc.L _ cls, _) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -------------------------- The message appeared after inserting data CSeq a = CSeq [a] instance (context => CDelimeter) CProd CSeq a where produce context (CSeq x) = map (produce context) x ghc is from standard ubuntu package.

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haskell-compiler --version The Glorious Glasgow Haskell Compilation System, version 7.4.1

-- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8169 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler