#7633: Checkable "minimal complete definitions" ---------------------------------+------------------------------------------ Reporter: shachaf | Owner: Type: feature request | Status: patch Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.6.1 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: None/Unknown Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: 6028 | ---------------------------------+------------------------------------------ Comment(by dmwit): This might be a bit of feature creep, but I thought I would try to archive a bit of #haskell discussion: it might be worth thinking about how to do cross-class MINIMAL pragmas. For example, imagine a world where we had something like this: {{{ {-# LANGUAGE DefaultSignatures #-} class Functor f where fmap :: (a -> b) -> (f a -> f b) default fmap :: Traversable f => (a -> b) -> (f a -> f b) fmap = getId . traverse (Id . f) class Functor f => Traversable f where traverse :: Applicative f => (a -> f b) -> t a -> f (t b) traverse f = sequenceA . fmap f sequenceA :: Applicative f => t (f a) -> f (t a) sequenceA = traverse id }}} I might like to be able to say that either "fmap and sequenceA" or "traverse" are okay minimal definitions for the two classes together. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7633#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler