w">&#45;&gt;</span></span> <span><a href="#type-key">key</a> option</span></span></code></div><div class="spec-doc"><p>Find a simple alias from the set of aliases</p></div></div><div class="odoc-spec"><div class="spec value" id="val-subst" class="anchored"><a href="#val-subst" class="anchor"></a><code><span><span class="keyword">val</span> subst : <span>subst_loc:<span>( <span><a href="#type-key">key</a> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-key">key</a> option</span> )</span> <sp