Injective type families
Simon Peyton Jones
simonpj at microsoft.com
Fri Jan 8 11:41:42 UTC 2016
| > If I actually want to write backward-compatible type family code
| > GHC-8.0, I'd prefer to be able to enable TypeFamilies yet not
| > InjectiveTypeFamilies, and have GHC check that I am in the common
| Good point. I wonder if others agree.
Yes I agree (see my last email).
But I think the same flag should deal with the richer form of improvement in the new branch, eg
type family F a b = r | r a -> b, r b -> a
Is "InjectiveTypeFamilies" a good name for this? Or "TypeFamilyDependencies"? Or what?
More information about the ghc-devs