or-param-error"><span class="type-annotation"><a href="dart-core/Object-class.html">Object</a></span> <span class="parameter-name">error</span>, [</span> <span class="parameter" id="addError-param-stackTrace"><span class="type-annotation"><a href="dart-core/StackTrace-class.html">StackTrace</a></span> <span class="parameter-name">stackTrace</span></span> ])
            <span class="returntype parameter">&#8594; void</span>
          </span>
                  </dt>
        <dd>
          Adds an <code>error<