#13368: Derive superclasses automatically if possible -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #10607 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- So I don't forget, this is like #10607 along another axis. Instead of writing {{{#!hs newtype IO_ a = IO_ (IO a) deriving newtype (Functor, Applicative, Monad, MonadIO) }}} allow writing {{{#!hs newtype IO_ a = IO_ (IO a) deriving newtype MonadIO }}} with the same meaning, are there any technical restrictions to this? This gets annoying in large hierarchies where you need `Eq`, `Ord`, `Num`, `Fractional`, `Floating`, `Real` and `RealFrac` just to derive {{{#!hs newtype F32 = F32 Float deriving newtype RealFloat }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13368 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler