Java 没有找到适用于addAll的方法

给定以下Java代码：

public void addStuff(Collection<? extends Object> aCollection) {
    List<? extends Object> myList = new LinkedList<>(aCollection);
    myList.addAll(aCollection);
}

---

public void addStuff（Collection基本上：通配符是不可靠的，Java不假设通配符是相同的通配符
no suitable method found for addAll(Collection<CAP#1>)
    method Collection.addAll(Collection<? extends CAP#2>) is not applicable
      (argument mismatch; Collection<CAP#1> cannot be converted to Collection<? extends CAP#2>)
    method List.addAll(Collection<? extends CAP#2>) is not applicable
      (argument mismatch; Collection<CAP#1> cannot be converted to Collection<? extends CAP#2>)
  where CAP#1,CAP#2 are fresh type-variables:
    CAP#1 extends Object from capture of ? extends Object
    CAP#2 extends Object from capture of ? extends Object

public LinkedList(Collection<? extends E> c) {
    this();
    addAll(c);
}

public boolean addAll(Collection<? extends E> c) {
    return addAll(size, c);
}

public <E> void addStuff(Collection<E> aCollection) {
  List<E> myList = new LinkedList<>(aCollection);
  myList.addAll(aCollection);
}