Assertion failure with ExistentialQuantification and ApplicativeDo
{-# LANGUAGE ExistentialQuantification, ApplicativeDo #-}moduleBugwheredataTf=foralla.MkT(fa)runf::forallf.Functorf=>IO(Tf)runf=doreturn()MkTfa<-runfreturn$MkTfa
Bug.hs:11:18: error:ghc: panic! (the 'impossible' happened) (GHC version 8.6.3 for x86_64-unknown-linux): No skolem info: [a_a1nb[ssk:2]] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in ghc:Outputable pprPanic, called at compiler/typecheck/TcErrors.hs:2891:5 in ghc:TcErrorsPlease report this as a GHC bug: http://www.haskell.org/ghc/reportabug