de>.
          When using <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">hash</span></code> for a type that does not have <code class="computeroutput"><span class="identifier">hash_value</span></code> declared but does have an
          implicit conversion to a type that does, it would use that implicit conversion
          to hash it. Which can sometimes go very wrong, e.g. using a conversion
          to bool and only hashing to 2 