#11427: superclasses aren't considered because context is no smaller than the instance head -------------------------------------+------------------------------------- Reporter: phadej | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Blaisorblade): Possibly silly question: the extra expressivity here is behind a language flag, so why does its support reduce the normal language? Is the extra check (for non-bottomness) needed without recursive superclasses? - Is it hard to reproduce the old behavior with the new algorithm? - Or is it a bad idea, because then the examples in this bug would work normally and break with UndecidableSuperClasses? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11427#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler