#15763: GHC forbids kind signatures in data family instances -------------------------------------+------------------------------------- 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): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): No. `data` is a declaration (binding site) and has its own, restrictive syntax. On the other hand, the head of a `data instance` is a type, containing only occurrences, not binding sites. (Even the type variables are occurrences. They are magically and invisibly bound by an implicit `forall`.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15763#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler