message: fix node missing
diff: @@ -45,10 +45,9 @@ impl<'a> DependencyGraph<'a> {
  let mut graph = DiGraphMap::new();
  for module in &modules {
  let module_idx: ModuleIndex = *reverse_modules.get(&module.self_id()).unwrap();
  - let mut deps = module.immediate_dependencies();
  - if deps.is_empty() {
  graph.add_node(module_idx);
  - } else {
  + let mut deps = module.immediate_dependencies();
  + if !deps.is_empty() {
  // make the function stable.
  deps.sort();
  for dep in deps {
  