#8745: GeneralizedNewtypeDeriving is still not Safe -------------------------------------------------+------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: Resolution: | 7.8.1-rc1 Operating System: Unknown/Multiple | Keywords: Safe Type of failure: None/Unknown | Architecture: Test Case: | Unknown/Multiple should_fail/TcCoercibleFailSafe | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: -------------------------------------------------+------------------------- Changes (by nomeata): * testcase: => should_fail/TcCoercibleFailSafe Comment:
With this in place (is it tested by anything in the testsuite?)
One simple test case is in place (`typecheck/should_fail/TcCoercibleFailSafe`).
class Foo a where ... type role Foo representational
Why is that even accepted? I thought role annotation can only stricten roles (i.e. P→N, P→R, R→N), and we have decided that classes have role nominal by default, so I would expect `type role Foo representational` to be rejected even in non-Safe Haskell. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8745#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler