#15370: Typed hole panic on GHC 8.6 (tcTyVarDetails) -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Tritlo Type: bug | Status: merge Priority: high | Milestone: 8.6.1 Component: Compiler (Type | Version: 8.4.3 checker) | Keywords: TypeInType, Resolution: | TypedHoles 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 bgamari): Hmm, I'm afraid there is a piece that we are missing on `ghc-8.6`. `T15370` fails with {{{ ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.6.0.20180802 for x86_64-unknown-linux): tcTyVarDetails co_a1vS :: y_a1vK[sk:1] ~# x_a1vJ[sk:1] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1164:37 in ghc:Outputable pprPanic, called at compiler/basicTypes/Var.hs:497:22 in ghc:Var Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} when this is cherry-picked on `ghc-8.6`. Tritlo, do you think you could look into this? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15370#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler