title: Clang-Tidy: Calling a base constructor other than the copy constructor
body: <p>I'm getting the following message from Clang-Tidy:</p>
  <pre><code>Clang-Tidy: Calling a base constructor other than the copy constructor
  </code></pre>
  <p>The code is this:</p>
  <pre><code>#include &lt;memory&gt;
  #include &lt;set&gt;
  
  using namespace std;
  
  class Node : enable_shared_from_this&lt;Node&gt;
  {
  public:
      explicit Node(Node *parent = nullptr) : parent(parent) { parent-&gt;children.insert(shared_from_this()); }
      Node(const Node &amp;that) : parent(that.parent), children(that.children) {}
      
  private:
      Node *parent; // C++14 &quot;weak pointer&quot;
      set&lt;shared_ptr&lt;Node&gt;&gt; children;
  };
  </code></pre>
  <p>I can't find documentation for this message from Clang-Tidy anywhere.</p>
  <p>What does it mean and why is it giving it?</p>