#5862: Need kind annotations ---------------------------------+------------------------------------------ Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.1 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: None/Unknown Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ In his [http://www.typesandotherdistractions.com/2012/02/fun-with- xpolykinds-polykinded-folds.html blog post] Edward Kmett finds that he needs kind annotations. In particular, he wants to be able to say this: {{{ class Category (c :: k -> k -> *) where type Ob c :: k -> Constraint id :: Ob c a => c a a (.) :: (Ob c a, Ob c b, Ob c c) => c b c -> c a b -> c a c }}} Note that the kind of `Ob` must match the kind of `c`, so to declare its kind you need to mention the kind variable `k`, and that means `k` must be in scope.
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