#15683: coerce fails for Coercible type families -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: TypeFamilies Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #8177 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * related: => #8177 Comment: I think what you likely want is the ability to declare type families that aren't nominal in their arguments. Something like: {{{#!hs type role X representational type family X a }}} To be clear, GHC doesn't currently grant the ability to do this, but if it hypothetically did, then this would solve your problem. This is the scope of #8177. I'd go as far to say that this ticket is a duplicate of that one—do you agree? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15683#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler