In the wsdl, the type tns:TrackerWorkflowRuleArray is used by the type TrackerWorkflow but it does not exist in the wsdl file.
<xsd:complexType name="TrackerWorkflow">
<xsd:sequence>
<xsd:element name="field_id" type="xsd:int" />
<xsd:element name="is_used" type="xsd:int" />
<xsd:element name="rules" type="tns:TrackerWorkflowRuleArray" />
<xsd:element name="transitions" type="tns:TrackerWorkflowTransitionArray" />
</xsd:sequence>
</xsd:complexType>
wsdl:
https://demo.tuleap.net/plugins/tracker/soap/view-wsdl