#[derive(Default, Clone, Copy, PartialEq, PartialOrd, Ord, Eq, Debug, Hash)]
pub struct Iter<I: IntoIterator>(pub I);
#[derive(Default, Clone, Copy, PartialEq, PartialOrd, Ord, Eq, Debug, Hash)]
pub struct Len(pub usize);
#[derive(Default, Clone, Copy, PartialEq, PartialOrd, Ord, Eq, Debug, Hash)]
pub struct Fn<F>(pub F);
#[derive(Default, Clone, Copy, PartialEq, PartialOrd, Ord, Eq, Debug, Hash)]
pub struct Value<T>(pub T);
#[derive(Default, Clone, Copy, PartialEq, PartialOrd, Ord, Eq, Debug, Hash)]
pub struct Default;