#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 nomeata):
For example, we could say that with Safe Haskell the default roles (ie if you don't give an explicit signature) of any data type declared in that module are nominal rather than representational.
What would that mean for inferring a module as Safe? Is `A` in the example Safe or nor? Would a module only be safe if it annotates everything as “nominal”? It seems to me that any special handling of Safe Haskell module is doomed to fail, because we want to be able to infer modules as Safe, i.e. we’ll have code where we do ''not'' know whether they are intended to be used as Safe modules or not. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8827#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler