��けます:</p>

<span class='rusttest'>fn main() {
    let option = Some(5);
fn foo(x: i32) { }
if option.is_some() {
    let x = option.unwrap();
    foo(x);
}
}</span><pre class='rust rust-example-rendered'>
<span class='kw'>if</span> <span class='ident'>option</span>.<span class='ident'>is_some</span>() {
    <span class='kw'>let</span> <span class='ident'>x</span> <span class='op'>=</span> <span class='ident'>option</span>.<span class='ident'>unwrap</span>();
    <span class='ident'>foo</span>(<span c