#5498: Generalized newtype deriving allows creating of instances I can't create by hand -----------------------------------------------+--------------------------- Reporter: dterei | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 7.3 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: deriving/should_fail/T5498 | Difficulty: Unknown Blocking: | Blocked By: 1496 | Related Tickets: -----------------------------------------------+--------------------------- Changes (by simonpj): * testcase: => deriving/should_fail/T5498 Comment: Indeed. The program is indeed rejected, although the error message is not fantastic. I've added it as a test. I think you can enable GND in Safe Haskell. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/5498#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler