#14845: TypeInType, index GADT by constraint witness -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #13895 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
I suppose the difference in promoting and not promoting is in the error message, no?
Indeed! You'll get "Data constructor S can't be used in a type because it's a GADT" or something like tat, rather than the current mysterious one. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14845#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler