[Haskell-cafe] How Type inference work in presence of Functional Dependencies

Consider the code below : {-# LANGUAGE MultiParamTypeClasses,FlexibleInstances,FunctionalDependencies,UndecidableInstances,FlexibleContexts #-} class Foo a c | a -> c instance Foo Int Float f :: (Foo Int a) => Int -> a f = undefined Now when I see the inferred type of f in ghci

:t f

f :: Int -> Float

Now If I add the following code g :: Int -> Float g = undefined h :: (Foo Int a) => Int -> a h = g I get the error Could not deduce (a ~ Float) I am not able to understand what has happened here ? The restriction "Foo Int a" should have restricted the type of h to "Int -> Float" as shown in the inferred type of f. - Satvik