Function haskell_bits::functor::fmap

pub fn fmap<TCon: ?Sized, TIn, TOut, F, X: ?Sized>(
    f: F, 
    x: &X
) -> <TCon as WithTypeArg<TOut>>::Type where
    TCon: Functor + WithTypeArg<TIn> + WithTypeArg<TOut>,
    X: TypeApp<TCon, TIn>,
    F: Fn(&TIn) -> TOut,