#15868: Standard deriving should be less conservative when `UndecidableInstances` is enabled -------------------------------------+------------------------------------- Reporter: edsko | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Resolution: | Keywords: deriving Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #11008 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by edsko): Would simply refusing to add constraints without any type variables be sufficient to rule out examples like the one you are worried about? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15868#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler