n, what are potential causes of leaking the null inside it. Formally, nullability values form a lattice with partial order and upper bound operations. Practically, most of nullsafe core should remain agnostic over exact values of nullability (e.g. pattern-mathching over them should be a rare case. Core of typechecker should deal with subtyping and joins instead.)</p></aside><dl><dt class="spec type" id="type-t"><a href="#type-t" class="anchor"></a><code><span class="keyword">type</span> t</code><code> = </c