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    use serde::{de, ser};
    use std::borrow::Borrow;
    use std::cmp::Ordering;
    use std::fmt;
    use std::hash::{Hash, Hasher};

    pub(crate) const NAME: &str = "$__toml_private_Spanned";
    pub(crate) const START: &str = "$__toml_private_start";
    pub(crate) const END: &str = "$__toml_private_end";
    pub(crate) const VALUE: &str = "$__toml_private_value";

    /// A spanned value, indicating the range at which it is defined in the source.
    ///
    /// ```
    /// use serde_derive::Deserialize;
    /// use toml::Spanned;
    ///
    /// #[derive(Deserialize)]
    /// struct Value {
    ///     s: Spanned<String>,
    /// }
    ///
    /// let t = "s = \"value\"\n";
    ///
    /// let u: Value = toml::from_str(t).unwrap();
    ///
    /// assert_eq!(u.s.start(), 4);
    /// assert_eq!(u.s.end(), 11);
    /// assert_eq!(u.s.get_ref(), "value");
    /// assert_eq!(u.s.into_inner(), String::from("value"));
    /// ```
    #[derive(Clone, Debug)]
    pub struct Spanned<T> {
        /// The start range.
        start: usize,
        /// The end range (exclusive).
        end: usize,
        /// The spanned value.
        value: T,
    }

    impl<T> Spanned<T> {
        /// Access the start of the span of the contained value.
        pub fn start(&self) -> usize {
            self.start
        }

        /// Access the end of the span of the contained value.
        pub fn end(&self) -> usize {
            self.end
        }

        /// Get the span of the contained value.
        pub fn span(&self) -> (usize, usize) {
            (self.start, self.end)
        }

        /// Consumes the spanned value and returns the contained value.
        pub fn into_inner(self) -> T {
            self.value
        }

        /// Returns a reference to the contained value.
        pub fn get_ref(&self) -> &T {
            &self.value
        }

        /// Returns a mutable reference to the contained value.
        pub fn get_mut(&mut self) -> &mut T {
            &mut self.value
        }
    }

    impl Borrow<str> for Spanned<String> {
        fn borrow(&self) -> &str {
            self.get_ref()
        }
    }

    impl<T: PartialEq> PartialEq for Spanned<T> {
        fn eq(&self, other: &Self) -> bool {
            self.value.eq(&other.value)
        }
    }

    impl<T: Eq> Eq for Spanned<T> {}

    impl<T: Hash> Hash for Spanned<T> {
        fn hash<H: Hasher>(&self, state: &mut H) {
            self.value.hash(state);
        }
    }

    impl<T: PartialOrd> PartialOrd for Spanned<T> {
        fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
            self.value.partial_cmp(&other.value)
        }
    }

    impl<T: Ord> Ord for Spanned<T> {
        fn cmp(&self, other: &Self) -> Ordering {
            self.value.cmp(&other.value)
        }
    }

    impl<'de, T> de::Deserialize<'de> for Spanned<T>
    where
        T: de::Deserialize<'de>,
    {
        fn deserialize<D>(deserializer: D) -> Result<Spanned<T>, D::Error>
        where
            D: de::Deserializer<'de>,
        {
            struct SpannedVisitor<T>(::std::marker::PhantomData<T>);

            impl<'de, T> de::Visitor<'de> for SpannedVisitor<T>
            where
                T: de::Deserialize<'de>,
            {
                type Value = Spanned<T>;

                fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
                    formatter.write_str("a TOML spanned")
                }

                fn visit_map<V>(self, mut visitor: V) -> Result<Spanned<T>, V::Error>
                where
                    V: de::MapAccess<'de>,
                {
                    if visitor.next_key()? != Some(START) {
                        return Err(de::Error::custom("spanned start key not found"));
                    }

                    let start: usize = visitor.next_value()?;

                    if visitor.next_key()? != Some(END) {
                        return Err(de::Error::custom("spanned end key not found"));
                    }

                    let end: usize = visitor.next_value()?;

                    if visitor.next_key()? != Some(VALUE) {
                        return Err(de::Error::custom("spanned value key not found"));
                    }

                    let value: T = visitor.next_value()?;

                    Ok(Spanned { start, end, value })
                }
            }

            let visitor = SpannedVisitor(::std::marker::PhantomData);

            static FIELDS: [&str; 3] = [START, END, VALUE];
            deserializer.deserialize_struct(NAME, &FIELDS, visitor)
        }
    }

    impl<T: ser::Serialize> ser::Serialize for Spanned<T> {
        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: ser::Serializer,
        {
            self.value.serialize(serializer)
        }
    }