#13598: role annotation for newtype (partially?) ignored? -------------------------------------+------------------------------------- Reporter: edsko | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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): Role annotations on newtypes are less interesting when the newtype constructor is in scope. In your case, GHC reduces `Coercible (C a) Int` to `Coercible o Int` and away it goes. And indeed if you hide the `MkC` constructor (via the usual import/export mechanism), `fooC` fails because of ambiguity. I do see how this is potentially confusing, however. A concrete suggestion for improvement in documentation is always welcome. If you agree with my analysis, please close the ticket. Thanks! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13598#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler