#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):

but I assume the same code is used to actually generate the instances in those two cases, right?

Right, the whole point is to make those work the same. Either way(e.g. empty case or error) works for me. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7401#comment:37> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler