#8851: Standalone deriving and GND behave differently -------------------------------------------------+------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.8.1 Component: Compiler (Type checker) | Version: Resolution: | 7.8.1-rc2 Operating System: Unknown/Multiple | Keywords: Type of failure: None/Unknown | Architecture: Test Case: | Unknown/Multiple deriving/should_compile/T8851 | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: -------------------------------------------------+------------------------- Comment (by goldfire): You have a better perspective on the difficulty of implementation here, so I'm happy enough to agree. It does seem a little silly that we can accept `deriving instance Parsing MyParser` (with no context at all) but not `newtype MyParser ... deriving Parsing`. But, this behavior is fully consistent with the articulation of the two `deriving` features, so there's nothing wrong with it. And, keeping the code simpler when the fix for users is so trivial is a good thing. Thanks for taking another look. We should modify the test case to reflect this change. I can do that later this week when I spend some time working on GHC. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8851#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler