ly_action &gt;, boost::units::unit&lt; Dim, System &gt;, Y&gt;">plain_return_type_2</a><span class="special">&lt;</span><span class="identifier">arithmetic_action</span><span class="special">&lt;</span> <span class="identifier">multiply_action</span> <span class="special">&gt;</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">units</span><span class="special">::</span><span class="identifier">unit</span><span class="special">&lt