/div><dl><dt class="spec value" id="val-check"><a href="#val-check" class="anchor"></a><code><span class="keyword">val</span> check : <span>what:<a href="../Nullability/index.html#type-t">Nullability.t</a></span> <span>&#45;&gt;</span> <span>by_rhs_upper_bound:<a href="../Nullability/index.html#type-t">Nullability.t</a></span> <span>&#45;&gt;</span> <span><span>(unit, <a href="index.html#type-violation">violation</a>)</span> <a href="../../IStdlib/index.html#module-IStd">IStdlib.IStd</a>.result</span></cod