#8631: Need ImpredicativeTypes for GeneralizedNewtypeDeriving? -------------------------------------+------------------------------------ Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by nomeata): Looking into Q1. There is some code temporarily enabling certain extension (`EmptyCase`, `ScopedTypeVariables` and `KindSignatures`) in `renameDeriv`, but these just affect the renamer; the error message we see occurs later, and I don’t see how we can enable `ImpredicativeTypes` in a scoped way, i.e. only applying to the code generated by GND. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8631#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler