#13365: Kind-inference for poly-kinded GADTs -------------------------------------+------------------------------------- Reporter: crockeea | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 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): Ryan nailed it. This is a CUSK issue. When you have a [https://downloads.haskell.org/~ghc/master/users-guide/glasgow_exts.html #complete-user-supplied-kind-signatures-and-polymorphic-recursion CUSK], inference runs quite differently from when you don't. The error message is actually correct, given that we're doing non-CUSK inference here. What would be better is an `NB: Adding a complete user-specified kind signature might help`. Not clear how easy or hard it would be to know when to add the `NB`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13365#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler