#14490: TTG Snags -------------------------------------+------------------------------------- Reporter: alanz | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #14482 | Differential Rev(s): Wiki Page: | ImplementingTreesThatGrow | -------------------------------------+------------------------------------- Comment (by simonpj): Why does Plan B not work in 8.0.2? This works: {{{ {-# LANGUAGE TypeFamilies, GADTs, FlexibleInstances, StandaloneDeriving, DeriveDataTypeable #-} module Foo where import Data.Data data T a where MkT :: XT a -> a -> T a type family XT a type instance XT Bool = Int deriving instance Data (T Bool) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14490#comment:29 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler