a href="../../IR/Procdesc/Node/index.html#type-t">IR.Procdesc.Node.t</a> <span class="arrow">&#45;&gt;</span></span>
  <span>f:<span>(<span>unit <span class="arrow">&#45;&gt;</span></span> <span class="type-var">'a</span>)</span> <span class="arrow">&#45;&gt;</span></span>
  <span class="type-var">'a</span>;</span></code></li></ol><code><span>}</span></code></div><div class="spec-doc"><p>These callbacks are used to break the dependency cycles between some modules. Specifically, we put here functions needed 