#10905: Incorrect number of parameters in "role" errors -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: roles Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by simonpj): I don't think my reasoning was any deeper than the comment says. In the example in the Description, the roles are a distraction from the main point: the constructor isn't in scope. They just get in the way, and for most people will be mysterious and confusing. Do we even want to see these role, or perhaps the roles of type constructors we have decomposed on the way to getting this error? To put it another way, can you give an example of where they are useful? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10905#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler