#15552: Infinite loop/panic with an existential type. -------------------------------------+------------------------------------- Reporter: howtonotwin | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Resolution: | Keywords: TypeInType, | TypeFamilies Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: #14723 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Another idea for (1): just eliminate the "optimisation" in `TcHsType.zonkTyVarOcc`. Types generally have no sharing, so we may not be gaining much by increasing sharing her. NB: in `TcMType.zonkTcTyVar` we could apply this optimisation; for some reason we don't even try to do that too. Another idea: maintain (statefully) a map from (meta) `TyVar` to `TyVar`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15552#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler