#15870: No skolem info panic -------------------------------------+------------------------------------- Reporter: sheaf | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.6.3 Component: Compiler (Type | Version: 8.6.2 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): I know why the crash happens. * In the instance decl we bring into scope the skolems of the instance * Then, we process the local family instance equation. In doing so we call the dreaded `tcFamTyPats` -- and it calls `solveEqualities` (wrongly I believe) * This `solveEqualities` tries to report an error; but it can't see the skolems, hence the panic. Really `solveEqualities` should only be called in an empty type environment. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15870#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler