#4815: Instance constraints should be used when deriving on associated data types -------------------------------------+------------------------------------- Reporter: batterseapower | Owner: Type: feature request | Status: new Priority: low | Milestone: Component: Compiler | Version: 6.12.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by rwbarton): I would expect it to type check, because an associated family instance is sugar for an ordinary data family instance and I can't understand what it would mean to put a constraint on such an instance (or why I would want to; it feels like the old datatype contexts). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/4815#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler