title: Can a "dataType" instance appear as a sequence diagram lifeline?
body: <p>A UML datatype is defined as follows:</p>
  
  <blockquote>
    <p>A DataType is a kind of Classifier. DataType differs from Class in that instances of a DataType are identified only by their value. All instances of a DataType with the same value are considered to be equal instances.</p>
  </blockquote>
  
  <p>Hence we can have an object that is an instance of a data type, but it does not have an identity and is only defined by its attributes.</p>
  
  <p>My question is the following: is it valid to have a lifeline in a UML sequence diagram that represents such an object instantiated from a dataType?</p>
  
  <p>Although I don't see anything against it in the specification, I have never seen it in any example, thus I am curious.</p>