i assume https://github.com/JohnLato/safe-bugtest/blob/master/Main.hs#L13should
say
putStrLn "Should print \"Pos (2)\""
rather than -2?
On Mon, Oct 7, 2013 at 1:23 AM, Carter Schonwald wrote: ooo, thats illuminating. thanks for cooking that up On Mon, Oct 7, 2013 at 1:13 AM, John Lato On Sun, Oct 6, 2013 at 10:14 PM, Ryan Newton On Sun, Oct 6, 2013 at 6:28 PM, Ganesh Sittampalam - Referential transparency: e.g. no unsafePerformIO - Module boundary control: no abstraction violation like Template Haskell and GeneralizedNewtypeDeriving
- Semantic consistency: importing a safe module can't change existing
code, so no OverlappingInstances and the like Is this change necessary to preserve the existing properties, or are you hoping to add a new one? I'm not currently aware of ways to break these invariants *just* with
GHC.Generics. Hmm, but I would like to know why it is marked trustworthy
and not inferred-safe... How about this demo repo? https://github.com/JohnLato/safe-bugtest I'm really not a safe haskell expert, but I believe this is a
demonstration of using GHC.Generics to violate a module's abstraction
boundaries with SafeHaskell enabled. If I'm incorrect, I would appreciate if somebody could explain my error.
If, however, I'm correct, then I think that Ryan's proposal of marking
GHC.Generics Unsafe is the best way to remedy the problem. A possible stumbling block may involve base and package-trust, but I'm
not certain of the current status. John L. _______________________________________________
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