ss="n">in</span><span class="p">)</span> <span class="kd">::</span> <span class="n">self</span> <span class="c">!! l.h.s. domain instance</span>
  <span class="k">class</span><span class="p">(</span><span class="n">domain_type</span><span class="p">),</span><span class="k">intent</span><span class="p">(</span><span class="n">in</span><span class="p">)</span> <span class="kd">::</span> <span class="n">d2</span> <span class="c">!! r.h.s. domain instance</span>
  <span class="n">domain</span> <span class="o">=