#7401: Can't derive instance for Eq when datatype has no constructor, while it is trivial do do so. -------------------------------------+------------------------------------- Reporter: jpbernardy | Owner: osa1 Type: feature request | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.6.1 Resolution: | Keywords: deriving, Operating System: Unknown/Multiple | newcomer Type of failure: GHC rejects | Architecture: valid program | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: Phab:D978 -------------------------------------+------------------------------------- Comment (by osa1): How should we proceed about this? Like @rwbarton mentioned in #10577, none of these is a part of the standard, so I think we can change behavior of standalone deriving to introduce an empty case, and then also change EmptyDataDecls deriving to make the behavior consistent. Should we move this discussion to the mailing list for feedbacks? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7401#comment:40 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler