#7701: compiler exception when -> is used instead of => in instance definition -------------------------------+-------------------------------------------- Reporter: erantapaa | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.4.2 | Keywords: Os: MacOS X | Architecture: x86 Failure: Compile-time crash | Blockedby: Blocking: | Related: -------------------------------+-------------------------------------------- When running ghci on the attached file, the following exception is raised: {{{ *** Exception: compiler/rename/RnSource.lhs:430:14-81: Irrefutable pattern failed for pattern Data.Maybe.Just (inst_tyvars, _, SrcLoc.L _ cls, _) }}} It seems to stem from accidentally using -> instead of => in the following instance definition: {{{ instance (ListConcat xs ys zs) -> ListConcat (x ::: xs) ys (x ::: zs) where listConcat = undefined }}} -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7701 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler