#12980: Unlifted class method rejected -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: | LevityPolymorphism Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by oerjan): * cc: oerjan (added) Comment: Replying to [comment:1 simonpj]:
Certainly should be ok for multi-method classes. I'm not quite sure about the single-method case, because of the interaction with newtypes -- but I think there's a case for using data types in the single-method case too.
Alternatively, since fields cannot be levity-polymorphic (at least without extra indirection), you could restrict the newtype optimization to methods of kind `Type`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12980#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler