9 Jan
2017
9 Jan
'17
5:22 p.m.
On Mon, Jan 9, 2017 at 1:32 PM, Richard Eisenberg
I agree with David that using explicit `coerce`s can be quite verbose and may need ScopedTypeVariables and InstanceSigs. But visible type application should always work, because class methods always have a fixed type argument order.
Oh, I missed this bit. That claim is not quite true. I could have something like class Two f where two :: (Integral a, Num b) => proxy (f a b) -> String Unless the package defining this class promises not to, its maintainer could later change that to two :: forall b a proxy . (Integral a, Num b) => proxy (f a b) -> String which could silently break code. Or change the position of the proxy argument and loudly break code.