Iterable<ModelElement> usedElements

Gather all the used elements, from the parameters and return type, for example E.g. method Iterable blah(List foo) will return Iterable, String, List, int

Source 

Iterable<ModelElement> get usedElements {
  final set = new Set<ModelElement>();
  if (modelType != null) {
    if (modelType.isFunctionType) {
      if (modelType.returnElement != null) {
        set.addAll(modelType.returnElement.usedElements);
      }
      if (canHaveParameters) {
        set.addAll(parameters.map((p) => p.usedElements).expand((i) => i));
      }
    } else if (modelType.element != null) {
      set.add(modelType.element);
      if (modelType.isParameterizedType) {
        set.addAll(modelType.typeArguments
            .map((arg) => arg.element.usedElements)
            .expand((i) => i));
      }
    }
  }
  return set;
}