#8263: allow duplicate deriving / standalone deriving -------------------------------------+------------------------------------- Reporter: aavogt | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I'm also inclined to reject this idea. Given the current richness of `deriving` language, it's possible to derive two instances which are //almost// the same but with subtle differences, e.g., {{{#!hs deriving stock instance Show Bool deriving newtype instance Show Bool }}} I imagine trying to detect duplicate instances would be a large headache. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8263#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler