Re: Unboxed Vectors of newtype'd values

Andres Löh wrote:

Yes, because these are superclasses of Unbox. So can't you simply say this:

...

newtype Foo = Foo Int deriving (Eq, Show, Unbox, M.MVector MVector, G.Vector Vector)

I don't think this should work. This is the basic set up: class G.Vector v a where basicLength :: v a -> Int ... data family Vector a newtype instance Vector Int = V_Int ... instance G.Vector Vector Int where basicLength (V_Int ...) = ... ... I don't understand what GeneralizedNewtypeDeriving does with deriving(G.Vector Vector) in this situation but it can't possibly do anything sensible without a data instance Vector Foo. The fact that it doesn't fail is just a bug, IMO. Roman