title: SonarQube doesn't see method reference
body: <p>I have private method in my class.</p>
  
  <pre><code>public class MyClass {
       public void method(){
           ....
           List&lt;String&gt; filteredPaths = Arrays.asList(paths).stream().filter(this::validate).collect(Collectors.toList());
           ....
       }
       private boolean validate(String path){
          ...
       }
  }
  </code></pre>
  
  <p>I see major issue:</p>
  
  <pre><code>Private method 'validate' is never used.
  </code></pre>
  
  <p>Is this issue known?</p>
  
  <p>How to fix it? workarounds?</p>