#12040: Code that builds on 7.8.4 and 7.10.3 but fails with requiring UndecidableInstances on 8.0.1-rc4 -------------------------------------+------------------------------------- Reporter: dmcclean | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.0.1 checker) | Resolution: | Keywords: Operating System: Linux | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by dmcclean): Thanks thornie. Do you have a position on whether the issue is with 7.10.3 being too permissive or 8.0.1 being too restrictive? Beyond "it makes sense to me" and "it used to work", I don't have a good handle on how to go about deciding whether this code is actually in line with the rules. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12040#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler