#16263: GHC accepts illegal constraint in kind -------------------------------------+------------------------------------- Reporter: goldfire | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.6.3 Resolution: | Keywords: TypeInType, | newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Good spot! But there is code in GHC that specifically deals with equality constraints (only) in kinds: see * `Inst.tcInstTyBinder`. * `dc_theta_illegal_constraint` in `TcHsType.tcTyVar` (which deals with promoting data constructors) I talked with Richard about this last night. I think we agreed that we can systematically and consistently support equality constraints in types. If so, we should un-do the commit you reference. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16263#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler