#13959: substTyVar's definition is highly dubious -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): Thanks for digging into this further. My question is: where do the arguments to `mkVarSet` come from? Why don't they already have the kind variables in the lists? (They probably should!) My hunch is that the assertion failures you're seeing are genuine -- that is, they suggest real latent bugs. So, I propose this solution: keep digging! :) More concretely, point us to a small sampling (1 might be a suitable small number) of places where this `mkVarSet` call happens, and see if you can describe the context for where that list of variables comes from. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13959#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler