Identity of the Policy Merge Operation

Here is another edge case. The following policy expression (Policy22.xml in the WS-Policy Interop Scenarios Pack) has one empty policy alternative = that is, no behavior is specified. Merging the policy that has one empty policy alternative with another policy X produces a new policy that is same as X.

<wsp:Policy xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy">
  <wsp:ExactlyOne>
    <wsp:All />
  </wsp:ExactlyOne>
</wsp:Policy>

A policy with one empty policy alternative is the identity of the policy merge operation.