title: Error recovery and parse trees in Anltr4
body: <p>Is it possible to instruct the error recover mechanism from Antlr4 to build an empty tree for a given rule with errors?</p>
  
  <p>I don't want to lose the whole parse tree but only the subtrees with respect to the root rule with parsing issues.</p>
  
  <p>If we have something like:</p>
  
  <pre><code>ruleA : ruleB | ruleC;
  ruleB : something
        | somethingElse;
  ruleC: ...;
  </code></pre>
  
  <p>If subrule <code>something</code> throws a NoViableAltException for instance, then I don't want the parse tree for ruleB. </p>