title: PropType is defined but prop is never used
body: <pre><code>const propTypes = {
    prop1: PropTypes.string,
    prop2: PropTypes.string,
    prop3: PropTypes.number,
  };
  
  const something = (props) =&gt; ((props.props2 &gt; 0 &amp; props.prop1 === props.props3) ?
    t('translation/abc')
    : t('translation/def'));
  </code></pre>
  
  <p>why does the component throw lint error <code>PropType is defined but prop is never used</code> for all three props <code>prop1, prop2, prop3</code>?</p>