#10489: Panic in TcEvidence due to wrong role -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: highest | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- This single line tickles it: {{{ convert d = let d' = case d of '0' -> '!' in d' }}} produces {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.11.20150604 for x86_64-apple-darwin): ASSERT failed! file compiler/typecheck/TcEvidence.hs line 600 Sym cobox_af8M Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} The failing assertion is about roles. Will look into this tomorrow. Labeling this "highest" because it's a very silly regression. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10489 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler