#14880: GHC panic: updateRole -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler (Type | Version: 8.2.2 checker) | Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: #15076 | Differential Rev(s): Phab:D4769 Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): Before we continue drilling in that direction, are these results reproducible? Timing is notoriously fickle, and I think it would be wise to make sure we know what we're getting into here. Also, I do think it's worthwhile to still measure allocations, just as another data point. If the `FV`/`VarSet` change isn't the driving force here, then what is? I recommend removing the code that adds the fvs of a variable's kind (without replacing this logic with anything) and testing again. That should surely take less time. (Be careful, e.g., by comparing `-ddump-tc- trace`s, that GHC's overall behavior doesn't change by doing this.) Then, add the `closeOverKinds`. Maybe the algorithm in `closeOverKinds` (simple though it is) is somehow grossly inefficient. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14880#comment:78 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler