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    use crate::iter::FromIterator;

    /// Collapses all unit items from an iterator into one.
    ///
    /// This is more useful when combined with higher-level abstractions, like
    /// collecting to a `Result<(), E>` where you only care about errors:
    ///
    /// ```
    /// use std::io::*;
    /// let data = vec![1, 2, 3, 4, 5];
    /// let res: Result<()> = data.iter()
    ///     .map(|x| writeln!(stdout(), "{}", x))
    ///     .collect();
    /// assert!(res.is_ok());
    /// ```
    #[stable(feature = "unit_from_iter", since = "1.23.0")]
    impl FromIterator<()> for () {
        fn from_iter<I: IntoIterator<Item = ()>>(iter: I) -> Self {
            iter.into_iter().for_each(|()| {})
        }
    }