#9163: Ptr should have a phantom role -------------------------------------+------------------------------------ Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 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 goldfire): While I hear Austin's concerns, I tend to agree with Simon here. We don't want to consider `Ptr Int` and `Ptr Bool` to be the same types, but we ''do'' want to allow a knowledgeable programmer to get from one to the other for free. This seems to be a great use case for `coerce`. This idea extends to other cases where GHC infers phantom roles. In case it got lost, I'll ask again: why is `Ptr` a datatype, not a newtype? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9163#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler