#15810: Kind inference error in classes -------------------------------------+------------------------------------- Reporter: goldfire | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5305 Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
Did you mean for the last example in comment:4 to be different than the first?
Yes I did. Now fixed. Data type decls (in GADT style) are different to class decls. In a data type decl the type variables from the head do not scope over the individual data con signatures. So your example really reads {{{ data T a wher MkT :: forall k a. T (a :: k) }}} and the following would be equally acceptable {{{ data T a wher MkT :: T (b :: k) }}} But with classes the type variables from the class header do indeed scope over the method declarations. So they are already inconsistent in that sense. I still say "no bug here" :-). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15810#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler