#8827: Inferring Safe mode with GeneralizedNewtypeDeriving is wrong -------------------------------------+------------------------------------ Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: 8226, 8745 -------------------------------------+------------------------------------ Comment (by dterei): What of this: * nominal by default when constructors aren't all exported * representational by default when all constructors are exported I understand the concern with (C) and the burden, I'm just not sure how high it is with some heuristics applied as suggested above. I like this approach (although I may be missing some corner cases) as it matches what I feel is a good high level starting point that GND and surrounding infrastructure (coercion) shouldn't allow you to write code that you couldn't write by hand unless explicitly opted-in by the library author. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8827#comment:23 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler