'kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>data</span>: <span class='ident'>Vec</span><span class='op'>&lt;</span><span class='ident'>i32</span><span class='op'>&gt;</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='number'>1</span>, <span class='number'>2</span>, <span class='number'>3</span>];
    <span class='lifetime'>&#39;b</span>: {
        <span class='comment'>// &#39;b is as big as we need this borrow to be</span>
       