Stream ordering bound

[ydewit]

While looking into fold_commutative, reduce_commutative, max etc implementations, I realized that the implementation adds a trait bound O: MinOrder<NoOrder, Min = NoOrder>. This seems to enforce that any ordering is accepted as long as it is equal or above NoOrder. This obviously make sense since implementations that do not depend on ordering can accept any streams with any ordering.

impl<'a, T, L, B, O> Stream<T, L, B, O>
where
    L: Location<'a>,
    O: MinOrder<NoOrder, Min = NoOrder>,

However, I was wondering why the Stream definition does not enforce that all ordering types do participate in the MinOrder trait, or more generically a Boundedness trait.

pub struct Stream<T, L, B, Order = TotalOrder> {
    location: L,
    pub(crate) ir_node: RefCell<HydroNode>,

    _phantom: PhantomData<(T, L, B, O)>,
}