Unless imported, or from an earlier GHCi line. So yes, for imported
#12792: Wrong error message when using a data type as a class instance head -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata): things one could do better. Maybe that is useful enough to do. I think it would. (I’m still not convined that it’s not possible otherwise. If the renamer knows about what “Names” have which “methods” (and it seems it does, given the error message), then surely it must know what “Names” can have “methods” in the first place – namely classes. But I should just try it myself, or at least read the code carefully, instead of rambling here.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12792#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler