#8566: Panic with kindFunResult -------------------------------------+------------------------------------ Reporter: dreixel | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.7 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: polykinds/T8566 | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by goldfire): I would say that `unA` in Pedro's (dreixel's) most recent example is indeed ill-typed -- it's an existential record selector, much like {{{ data Ex where MkEx :: { unEx :: [a] } -> Ex }}} The error message, though, could be improved. With `unEx`, GHC accepts the declaration but then prevents any use of `unEx` in an expression position. I propose that the same be done with `unA`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8566#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler