r">'a</span>, <span><span class="type-var">'b</span> <a href="#type-structure">structure</a></span>)</span> <a href="#type-field">field</a></span> <span class="arrow">&#45;&gt;</span></span> int</span></code></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-field_type"><a href="#val-field_type" class="anchor"></a><code><span><span class="keyword">val</span> field_type : <span><span><span>(<span class="type-var">'a</span>, <span class="type-var">'b</span>)</span> <a href="#type-fiel