ID 492700 - Parameter Reference Expressions: parameter references that use a relative path to an ancestor node are ignored by NodegraphAPI.GetExpressionReferences()

Problem summary:

In a parameter Reference Expression, parameter references that use a relative path to an ancestor node (using '^' characters) do not contribute to the references returned by `NodegraphAPI.GetExpressionReferences()`. The referenced nodes are also consequently omitted from the set returned by `NodegraphAPI.Util.GetAllContributingNodes()`.

Steps to reproduce:

1. In a project with no parameter expressions, configure a parameter as a Reference Expression using '^' characters to reference a parameter on an ancestor node, e.g. "=^/foo".
2. Execute 'NodegraphAPI.GetExpressionReferences()' and observe the return value.

Expected behaviour:

The reference is included in the return value.

Actual behaviour:

The reference is not include; an empty set is returned.

Workaround:

No known workaround.

Tested versions/platforms:

• 3.5v5 - Unaffected
• 3.6v1 - Affected
• 4.0v5 - Affected