#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: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * related: => #13895 Comment: I too have hit this limitation—or rather, I have hit this error message—in #13895. But in the case of #13895, the root of the issue is impredicativity, whereas here I'm not sure that's the case. I'd be curious to hear goldfire's reasoning for why this restriction is in place, since the [http://git.haskell.org/ghc.git/blob/34834234fff4a9dd0408d3b29e001cd132665327... source code] doesn't have much in the way of an explanation. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14845#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler