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    #[derive(Clone)]
    pub(crate) struct AnyValue {
        inner: std::sync::Arc<dyn std::any::Any + Send + Sync + 'static>,
        // While we can extract `TypeId` from `inner`, the debug repr is of a number, so let's track
        // the type_name in debug builds.
        id: AnyValueId,
    }

    impl AnyValue {
        pub(crate) fn new<V: std::any::Any + Clone + Send + Sync + 'static>(inner: V) -> Self {
            let id = AnyValueId::of::<V>();
            let inner = std::sync::Arc::new(inner);
            Self { inner, id }
        }

        pub(crate) fn downcast_ref<T: std::any::Any + Clone + Send + Sync + 'static>(
            &self,
        ) -> Option<&T> {
            self.inner.downcast_ref::<T>()
        }

        pub(crate) fn downcast_into<T: std::any::Any + Clone + Send + Sync>(self) -> Result<T, Self> {
            let id = self.id;
            let value =
                ok!(std::sync::Arc::downcast::<T>(self.inner).map_err(|inner| Self { inner, id }));
            let value = std::sync::Arc::try_unwrap(value).unwrap_or_else(|arc| (*arc).clone());
            Ok(value)
        }

        pub(crate) fn type_id(&self) -> AnyValueId {
            self.id
        }
    }

    impl std::fmt::Debug for AnyValue {
        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
            f.debug_struct("AnyValue").field("inner", &self.id).finish()
        }
    }

    #[derive(Copy, Clone)]
    pub struct AnyValueId {
        type_id: std::any::TypeId,
        #[cfg(debug_assertions)]
        type_name: &'static str,
    }

    impl AnyValueId {
        pub(crate) fn of<A: ?Sized + 'static>() -> Self {
            Self {
                type_id: std::any::TypeId::of::<A>(),
                #[cfg(debug_assertions)]
                type_name: std::any::type_name::<A>(),
            }
        }
    }

    impl PartialEq for AnyValueId {
        fn eq(&self, other: &Self) -> bool {
            self.type_id == other.type_id
        }
    }

    impl Eq for AnyValueId {}

    impl PartialOrd for AnyValueId {
        fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
            self.type_id.partial_cmp(&other.type_id)
        }
    }

    impl Ord for AnyValueId {
        fn cmp(&self, other: &Self) -> std::cmp::Ordering {
            self.type_id.cmp(&other.type_id)
        }
    }

    impl std::hash::Hash for AnyValueId {
        fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
            self.type_id.hash(state);
        }
    }

    impl std::fmt::Debug for AnyValueId {
        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
            #[cfg(not(debug_assertions))]
            {
                self.type_id.fmt(f)
            }
            #[cfg(debug_assertions)]
            {
                f.debug_struct(self.type_name).finish()
            }
        }
    }

    impl<'a, A: ?Sized + 'static> From<&'a A> for AnyValueId {
        fn from(_: &'a A) -> Self {
            Self::of::<A>()
        }
    }

    #[cfg(test)]
    mod test {
        #[test]
        #[cfg(debug_assertions)]
        fn debug_impl() {
            use super::*;

            assert_eq!(format!("{:?}", AnyValue::new(5)), "AnyValue { inner: i32 }");
        }
    }