title: Regex Negative look ahead in ADFS claim rule
body: <p>I need to grant a claim to everyone not matching a particular LDAP attribute.  I want to use a regex with a negative look ahead to perform this "not" clause</p>
  
  <pre><code>c1:[Type == "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name", Value =~ "^(?!Test User).*$"]
   =&gt; issue(Type = "http://goofyclaim", Value = "youre not a tester");
  </code></pre>
  
  <p>the above rule doesn't seem to get satisfied by my test users.   Something wrong with  the regex? or does ADFS4.0 not support it.  I don't see any errors in the ADFS event logs.</p>
  
  <p>this is a win2016srv on a win2012r2 AD domain.</p>
  
  <p>for reference, this rule does work:</p>
  
  <pre><code>c1:[Type == "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name", Value =~ "(?i)^Test User1"]  
   =&gt; issue(Type = "http://somethignelseentreily", Value = "imispellwhendriving");
  </code></pre>