generalized newtype and type families is unsound
the code from http://joyoftypes.blogspot.com/2012/08/generalizednewtypederiving-is.html type checks in the release candidate
also see discussion here http://www.reddit.com/r/haskell/comments/y8kca/generalizednewtypederiving_is_very_very_unsafe/
(punch line: the generalized newtype deriving + type families or gadts allows users to write unsafeCoerce etc)
perhaps a simple near term solution is to have any module using generalized new type deriving be inferred to be unsafe by default?
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.6.1-rc1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |