#9200: Milner-Mycroft failure at the kind level -------------------------------------+------------------------------------- Reporter: ekmett | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 (Type checker) | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: GHC | Related Tickets: rejects valid program | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by simonpj): Is it ok to remove the para about "non-parametric" equations? Re your question, no that `S` doesn't have a CUSK, any more than {{{ data T a b = MkT (T a b) a b }}} does. It's "obvious" that `S`'s RHS has kind `*`, but only because you have mentally done kind inference on `S`'s right hand side. Of course, the example you give would be accepted in fact. Neither has a CUSK, but normal inference and generalisation suffices. There is no polymorphic recursion. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9200#comment:35 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler