s="at-tag">deprecated</span> unsafe, obviously; please add a comment why you need to use this and suppress this warning locally with [@alert &quot;-deprecated&quot;]</li></ul></div></div><div class="odoc-spec"><div class="spec type anchored" id="type-needs_canon"><a href="#type-needs_canon" class="anchor"></a><code><span><span class="keyword">type</span> needs_canon</span></code></div><div class="spec-doc"><p>an abstract value that needs to be normalized; just <code>AbstractValue.t</code> under the hood too