or_error.html" class="api-reference"><code>value_or_error&lt;T, U&gt;</code></a>
 type into the <code>BOOST_OUTCOME_V2_NAMESPACE::convert</code> namespace.</p>

<p>Outcome&rsquo;s default <code>convert::value_or_error&lt;T, U&gt;</code> implementation explicitly
excludes Outcome <code>result</code> and <code>outcome</code> types from the default mechanism as
there is a major gotcha: the <code>value_or_error</code> matched type&rsquo;s <code>.value()</code> is often
not callable in constexpr as it can throw,