Command object inList constraint not available in a gsp

class Book {

   String title
   String state

   static constraints = {
      title(blank: false, size: 1..40)
      state(inList: ['active', 'loginDisabled', 'actionsDisabled'])
   }
}

class Operation {

   String state

   static constraints = {
      state(inList: ['active', 'loginDisabled', 'actionsDisabled'])
   }
}

def operation(Operation operationInstance) {
   operationInstance.state = 'active'	// Any valid value will do
   return [operationInstance: operationInstance]
}

<g:select id="state" name="state" from="${operationInstance.constraints.state.inList}" value="${operationInstance.state}"/>

Caused by MissingPropertyException: No such property: state for class: test.Operation