insert source_order in simplify

crates/ty_python_semantic/src/types/constraints.rs

@@ -2363,6 +2363,7 @@ impl<'db> InteriorNode<'db> {
                     // represent that intersection. We also need to add the new constraint to our
                     // seen set and (if we haven't already seen it) to the to-visit queue.
                     if seen_constraints.insert(intersection_constraint) {
+                        source_orders.insert(intersection_constraint, next_source_order);
                         to_visit.extend(
                             (seen_constraints.iter().copied())
                                 .filter(|seen| *seen != intersection_constraint)