  <span class="ident">mutability</span>: <span class="macro">option</span><span class="macro">!</span>(<span class="macro">keyword</span><span class="macro">!</span>(<span class="kw-2">mut</span>)) <span class="op">&gt;&gt;</span>
        <span class="ident">ident</span>: <span class="macro">syn</span><span class="macro">!</span>(<span class="ident">Ident</span>) <span class="op">&gt;&gt;</span>
        <span class="ident">colon_token</span>: <span class="macro">punct</span><span class="macro">!</span>(:) <