deduction error

gistfile1.txt

{-# LANGUAGE FlexibleContexts #-}
import qualified Data.Vector.Generic as G

fooG :: (G.Vector v Int) => Int -> v Int -> v Bool
fooG x = G.map (> x)

-- hello.hs:5:10:Could not deduce (G.Vector v Bool) arising from a use of ‘G.map’
-- from the context (G.Vector v Int)
--   bound by the type signature for
--              fooG :: G.Vector v Int => Int -> v Int -> v Bool
--   at hello.hs:4:9-50
-- In the expression: G.map (> x)
-- In an equation for ‘fooG’: fooG x = G.map (> x)

{-# LANGUAGE FlexibleContexts, Rank2Types, KindSignatures #-}
import qualified Data.Vector.Generic as G

fooG :: forall (v :: * -> *). (G.Vector v Bool, G.Vector v Int) => Int -> v Int -> v Bool
fooG x = G.map (> x)

{-# LANGUAGE FlexibleContexts, Rank2Types #-}
import qualified Data.Vector.Generic as G

fooG :: forall v. (G.Vector v Bool, G.Vector v Int) => Int -> v Int -> v Bool
fooG x = G.map (> x)

{-# LANGUAGE FlexibleContexts #-}
import qualified Data.Vector.Generic as G

fooG :: (G.Vector v Bool, G.Vector v Int) => Int -> v Int -> v Bool
fooG x = G.map (> x)