Function get_constant_info_references

crates/compile/src/graph.rs:100–135

(constant_info: &ConstantInfo)

      Some(acc)
    })
    .reduce(Acc::default, |mut l, r| {
      l.out_refs = merge_ref_maps(l.out_refs, r.out_refs);
      l.in_refs = merge_ref_maps(l.in_refs, r.in_refs);
      l.ungrounded.extend(r.ungrounded);
      for (k, v) in r.ind_groups {
        l.ind_groups.entry(k).or_insert(v);
      }
      l
    });

  SetupScan {
    graph: RefGraph { out_refs: acc.out_refs, in_refs: acc.in_refs },
    immediate_ungrounded: acc.ungrounded,
    ind_groups: acc.ind_groups,
  }
}

/// `name → {name} ∪ deps`-shaped reverse-edge fragment for one
/// constant, merged across the parallel scan.
fn mk_in_refs(name: &Name, deps: &NameSet) -> RefMap {
  let mut in_refs = RefMap::from_iter([(name.clone(), NameSet::default())]);
  for dep in deps {
    match in_refs.entry(dep.clone()) {
      Entry::Vacant(entry) => {
        entry.insert(NameSet::from_iter([name.clone()]));
      },
      Entry::Occupied(mut entry) => {
        entry.get_mut().insert(name.clone());
      },
    }
  }
  in_refs
}

/// Size-aware map union (drain the smaller side into the bigger).
fn merge_ref_maps(l: RefMap, r: RefMap) -> RefMap {
  let (smaller, mut bigger) = if l.len() < r.len() { (l, r) } else { (r, l) };
  for (name, set) in smaller {
    match bigger.entry(name) {