#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-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by simonpj): OK, but what does "access the symbols" mean, exactly? The kind of a type constructor may change if you change its implementation; and similarly its roles. I think it should be fine to coerce `T Age` to `T Int`, even if T's constructors are not visible, unless T's author declares T's role to be nominal. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8827#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler