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我有一个来自 Rust 编译器的生命周期/借用错误，我无法理解。问题似乎是 Rust 假设当一个参数传递给一个返回静态值引用的函数时，该参数引用也必须是静态的。

#[derive(Debug)]
struct TestThingy<'a> {
    label: &'a str,
}

const TEST_VALUES: [TestThingy; 3] = [
    TestThingy { label: "one" },
    TestThingy { label: "two" },
    TestThingy { label: "three" },
];

pub fn value_for_num(num: &str) -> Option<&'static TestThingy> {
    TEST_VALUES.iter().find(|value| value.label == num)
}

pub fn test_out_thingy() {
    let tmp_val = String::from("two");
    if let Some(test_thingy) = value_for_num(&tmp_val) {
        println!("test_thingy: {:?}", test_thingy);
    }
}

fn main() {
    test_out_thingy();
}

Rust 错误：error[E0597]: `tmp_val` does not live long …