#14845: TypeInType, index GADT by constraint witness -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: feature request | Status: closed Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.5 Resolution: fixed | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: | dependent/should_fail/T14845_fail1, | dependent/should_fail/T14845_fail2 Blocked By: | Blocking: Related Tickets: #13895, #15215, | Differential Rev(s): Phab:D4728 #15282 | Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * status: patch => closed * testcase: => dependent/should_fail/T14845_fail1, dependent/should_fail/T14845_fail2 * resolution: => fixed * related: #13895, #15215 => #13895, #15215, #15282 * milestone: => 8.6.1 Comment: Commit c63754118cf6c3d0947d0c611f1db39c78acf1b7 improves the error message substantially. As mentioned in comment:4, we can't actually allow this program until dependent types are available. The remaining task from this ticket is to document how a program like the one in comment:16 desugars into coercions at the Core Level. I've opened #15282 for this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14845#comment:21 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler