I have the issue with <md-autocomplete> component which is shown in this demo:
<md-autocomplete ng-pattern="..."> does not work. I would expect that if some text is entered into Tax field (like zzz) the field is be marked as red as only numbers [1..99] are accepted by regex ng-pattern="/^[1-9]\d?$/". Actually required works fine: when the field is empty, it is triggered as invalid.