ecial">)</span> <span class="special">&amp;</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">Z</span><span class="special">)</span> <span class="special">!=</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span></code>,
              then <code class="computeroutput"><span class="identifier">X</span><span class="special">-&gt;</span><span class="identifier">Z</span></code> is subrange