an class="identifier">R</span><span class="special">(</span><span class="identifier">T</span><span class="special">))</span>
        <span class="special">!=</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">S</span><span class="special">)</span></code>,
        the conversion direction is said to be <span class="bold"><strong>subranged</strong></span>,
        which means that <code class="computeroutput"><span class="identifier">R</span><span class="special">(<