Passing anonymous classes to private member functions
<p>Is it possible to use a class defined in an anonymous namespace as a parameter in a private member function?  I haven’t found a way to forward declare AnonymousHelperClass in the header.</p>

<pre><code>// C.h
class C
{
  // ...
private:
  void Boing(AnonymousHelperClass &amp;helper);
};
</code></pre>

<p>.  </p>

<pre><code>// C.cpp
namespace
{
  class AnonymousHelperClass
  {
    // . . . 
  };
}

C::Boing(AnonymousHelperClass &amp;helper)
{
  // ...
}
</code></pre>
