#7586: :kind command cannot show kind of type synonyms ---------------------------------+------------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.1 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: None/Unknown Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ Changes (by simonpj): * difficulty: => Unknown Comment: The `:kind` command takes a ''type'' not a ''name'' as its argument. So you can sy {{{ Prelude> :k [Int] }}} for example. would you expect this to work? {{{ Prelude> type T a b = Int Prelude> :k (Monad (T Int)) }}} Probably not. It's well-kinded but `T` is partially applied. OK, so how about this? {{{ Prelude> type T a b = Int Prelude> :k (T Int) }}} Now it's less obvious. Perhaps we should report `* -> *`, but it's clearly a hack ot do so. For the case you give where it's just a simple name, it is arguably really pedantic not to report the kind of the synonym. Really you should use `:info` when you just have a name. Suggestion: perhaps `:kind` (and `:type`), when applied to a name, should simply delegate to `:info`? Would that be better than some kind of hack to `:kind`? (Mind you `:info` is not printing nicely for polykinded things, yet.) Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7586#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler