--- /dev/null
+use std::fmt;
+use std::any::Any as StdAny;
+
+#[cfg(feature = "clone")]
+#[doc(hidden)]
+pub trait CloneToAny {
+ /// Clone `self` into a new `Box<Any>` object.
+ fn clone_to_any(&self) -> Box<Any>;
+}
+
+#[cfg(feature = "clone")]
+impl<T: Any + Clone> CloneToAny for T {
+ fn clone_to_any(&self) -> Box<Any> {
+ Box::new(self.clone())
+ }
+}
+
+macro_rules! define_any {
+ (#[$m:meta] $t:item $i:item) => {
+ /// A type to emulate dynamic typing.
+ ///
+ /// Every suitable type with no non-`'static` references implements `Any`. See the
+ /// [`std::any` documentation](https://doc.rust-lang.org/std/any/index.html) for more
+ /// details on `Any` in general.
+ ///
+ /// This trait is not `std::any::Any` but rather a type extending that for this library’s
+ /// purposes; most specifically, there are a couple of Cargo features that can be enabled
+ /// which will alter the constraints of what comprises a suitable type:
+ ///
+ /// <table>
+ /// <thead>
+ /// <tr>
+ /// <th title="The name of the Cargo feature to enable">Feature name</th>
+ /// <th title="If a type doesn’t satisfy these bounds, it won’t implement Any">Additional bounds</th>
+ /// <th title="Were these docs built with this feature enabled?">Enabled in these docs?</th>
+ /// </tr>
+ /// </thead>
+ /// <tbody>
+ /// <tr>
+ /// <th><code>clone</code></th>
+ /// <td><code><a class=trait title=core::clone::Clone
+ /// href=http://doc.rust-lang.org/std/clone/trait.Clone.html
+ /// >Clone</a></code></td>
+ #[cfg_attr(feature = "clone", doc = " <td>Yes</td>")]
+ #[cfg_attr(not(feature = "clone"), doc = " <td>No</td>")]
+ /// </tr>
+ /// <tr>
+ /// <th><code>concurrent</code></th>
+ /// <td><code><a class=trait title=core::marker::Send
+ /// href=http://doc.rust-lang.org/std/marker/trait.Send.html
+ /// >Send</a> + <a class=trait title=core::marker::Sync
+ /// href=http://doc.rust-lang.org/std/marker/trait.Sync.html
+ /// >Sync</a></code></td>
+ #[cfg_attr(feature = "concurrent", doc = " <td>Yes</td>")]
+ #[cfg_attr(not(feature = "concurrent"), doc = " <td>No</td>")]
+ /// </tr>
+ /// </tbody>
+ /// </table>
+ #[$m] $t
+ #[$m] $i
+ }
+}
+
+define_any! {
+ #[cfg(all(not(feature = "clone"), not(feature = "concurrent")))]
+ pub trait Any: StdAny { }
+ impl<T: StdAny> Any for T { }
+}
+
+define_any! {
+ #[cfg(all(feature = "clone", not(feature = "concurrent")))]
+ pub trait Any: StdAny + CloneToAny { }
+ impl<T: StdAny + Clone> Any for T { }
+}
+
+define_any! {
+ #[cfg(all(not(feature = "clone"), feature = "concurrent"))]
+ pub trait Any: StdAny + Send + Sync { }
+ impl<T: StdAny + Send + Sync> Any for T { }
+}
+
+define_any! {
+ #[cfg(all(feature = "clone", feature = "concurrent"))]
+ pub trait Any: StdAny + CloneToAny + Send + Sync { }
+ impl<T: StdAny + Clone + Send + Sync> Any for T { }
+}
+
+#[cfg(feature = "clone")]
+impl Clone for Box<Any> {
+ fn clone(&self) -> Box<Any> {
+ (**self).clone_to_any()
+ }
+}
+
+impl<'a> fmt::Debug for &'a Any {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.pad("&Any")
+ }
+}
+
+impl<'a> fmt::Debug for Box<Any> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.pad("Box<Any>")
+ }
+}