#10541: Expose kind information for type variables with reify -------------------------------------+------------------------------------- Reporter: spinda | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by goldfire): I think we can actually do a bit better. It should be possible to tell whether we fully know a type variable's kind, by looking through the (zonked) kind for any `MetaTv`s. If there aren't any, then the kind is fully known and can be reported. Otherwise, don't report. The problem with my approach here is that it's fragile, depending delicately on the order that GHC reads through a type. Perhaps your solution is better: report the kind only when it is robustly known, either through a kind annotation or other means. (For "other means", I mean, for example, when a type variable is in scope in a term, via !ScopedTypeVariables. These type variables are generally fully known.) But how do we know when the tyvar's kind is robustly known... or even just annotated? By the time `reify` is called, we've lost a lot of that information. There's ''something'' we can do for you in this space, but I'm not sure exactly what yet. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10541#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler