#11371: Bogus in-scope set in substitutions -------------------------------------+------------------------------------- Reporter: simonpj | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #11360 | Differential Rev(s): phab:D1792, Wiki Page: | phab:D1801, phab:D1802 -------------------------------------+------------------------------------- Comment (by niteria): Changing it to: {{{ empty_subst = mkEmptyTCvSubst $! mkInScopeSet $! tyCoVarsOfTypes (ty:args) }}} gives me: {{{ $ ("/data/users/bnitka/ghc-perf/ghc-after/inplace/test spaces/ghc- stage2" -c T5030.hs -fforce-recomp -no-user-package-db -rtsopts -fno-warn- tabs -fno-warn-missed-specialisations -fno-ghci-history -freduction- depth=300 +RTS -V0 -tT5030.comp.stats --machine-readable -P -RTS) ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.1.20160216 for x86_64-unknown-linux): exprToType CallStack (from -prof): GHC.withCleanupSession (compiler/main/GHC.hs:(464,1)-(473,27)) GHC.runGhc (compiler/main/GHC.hs:(437,1)-(442,26)) GHC.defaultErrorHandler (compiler/main/GHC.hs:(377,1)-(409,7)) CoreSyn.CAF (<entire-module>) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Is it worth looking at? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11371#comment:37 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler