Cannot convert from type T to type T?
<p>A strange error here using static factory pattern. What am I missing?  Here is the code:</p>

<pre><code>class subclass&lt;T&gt; extends immutablestruct&lt;T&gt;{
private immutablestruct f;
private T x;

    //constructor
&lt;T&gt; subclass(T y, immutablestruct&lt;T&gt; f ){
    this.x = y;  //this is there the error is
    this.f = f;
}
</code></pre>
