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//! impl bool {}

#[lang = "bool"]
impl bool {
    /// 如果 `bool` 是 `true`，则返回 `Some(t)`，否则返回 `None`。
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(bool_to_option)]
    ///
    /// assert_eq!(false.then_some(0), None);
    /// assert_eq!(true.then_some(0), Some(0));
    /// ```
    #[unstable(feature = "bool_to_option", issue = "80967")]
    #[inline]
    pub fn then_some<T>(self, t: T) -> Option<T> {
        if self { Some(t) } else { None }
    }

    /// 如果 `bool` 是 `true`，则返回 `Some(f())`，否则返回 `None`。
    ///
    /// # Examples
    ///
    /// ```
    /// assert_eq!(false.then(|| 0), None);
    /// assert_eq!(true.then(|| 0), Some(0));
    /// ```
    #[stable(feature = "lazy_bool_to_option", since = "1.50.0")]
    #[inline]
    pub fn then<T, F: FnOnce() -> T>(self, f: F) -> Option<T> {
        if self { Some(f()) } else { None }
    }
}